diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 7fc07a3f19f9..fbc007949cbd 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -5,6 +5,12 @@ These are notable changes in edx-platform.  This is a rolling list of changes,
 in roughly chronological order, most recent first.  Add your entries at or near
 the top.  Include a label indicating the component affected.
 
+XModule: Don't delete generated xmodule asset files when compiling (for
+instance, when XModule provides a coffeescript file, don't delete
+the associated javascript)
+
+Common: Make rake provide better error messages if packages are missing.
+
 Common: Repairs development documentation generation by sphinx.
 
 LMS: Problem rescoring.  Added options on the Grades tab of the
diff --git a/common/lib/xmodule/xmodule/static_content.py b/common/lib/xmodule/xmodule/static_content.py
index 4c4827e0aa5e..42fef65b1134 100755
--- a/common/lib/xmodule/xmodule/static_content.py
+++ b/common/lib/xmodule/xmodule/static_content.py
@@ -121,15 +121,23 @@ def _write_js(output_root, classes):
             type=filetype)
         contents[filename] = fragment
 
-    _write_files(output_root, contents)
+    _write_files(output_root, contents, {'.coffee': '.js'})
 
     return [output_root / filename for filename in contents.keys()]
 
 
-def _write_files(output_root, contents):
+def _write_files(output_root, contents, generated_suffix_map=None):
     _ensure_dir(output_root)
-    for extra_file in set(output_root.files()) - set(contents.keys()):
-        extra_file.remove_p()
+    to_delete = set(file.basename() for file in output_root.files()) - set(contents.keys())
+
+    if generated_suffix_map:
+        for output_file in contents.keys():
+            for suffix, generated_suffix in generated_suffix_map.items():
+                if output_file.endswith(suffix):
+                    to_delete.discard(output_file.replace(suffix, generated_suffix))
+
+    for extra_file in to_delete:
+        (output_root / extra_file).remove_p()
 
     for filename, file_content in contents.iteritems():
         (output_root / filename).write_bytes(file_content)
diff --git a/rakefile b/rakefile
index 20101a14db58..96bd4c2e96c2 100644
--- a/rakefile
+++ b/rakefile
@@ -1,9 +1,11 @@
-require 'json'
-require 'rake/clean'
-require './rakefiles/helpers.rb'
-
-Dir['rakefiles/*.rake'].each do |rakefile|
-    import rakefile
+begin
+    require 'json'
+    require 'rake/clean'
+    require './rakelib/helpers.rb'
+rescue LoadError => error
+    puts "Import faild (#{error})"
+    puts "Please run `bundle install` to bootstrap ruby dependencies"
+    exit 1
 end
 
 # Build Constants
diff --git a/rakefiles/assets.rake b/rakelib/assets.rake
similarity index 90%
rename from rakefiles/assets.rake
rename to rakelib/assets.rake
index 764d049a683e..c80b275c2734 100644
--- a/rakefiles/assets.rake
+++ b/rakelib/assets.rake
@@ -30,7 +30,7 @@ def coffee_cmd(watch=false, debug=false)
         #
         # So, instead, we use watchmedo, which works around the problem
         "watchmedo shell-command " +
-                  "--command 'node_modules/.bin/coffee -c ${watch_src_path}' " +
+                  "--command 'echo \">>> Change detected to ${watch_src_path}\" && node_modules/.bin/coffee -c ${watch_src_path}' " +
                   "--recursive " +
                   "--patterns '*.coffee' " +
                   "--ignore-directories " +
@@ -55,8 +55,9 @@ def sass_cmd(watch=false, debug=false)
           "#{watch ? '--watch' : '--update'} -E utf-8 #{sass_watch_paths.join(' ')}"
 end
 
+# This task takes arguments purely to pass them via dependencies to the preprocess task
 desc "Compile all assets"
-multitask :assets => 'assets:all'
+task :assets, [:system, :env] => 'assets:all'
 
 namespace :assets do
 
@@ -80,8 +81,9 @@ namespace :assets do
     {:xmodule => [:install_python_prereqs],
      :coffee => [:install_node_prereqs, :'assets:coffee:clobber'],
      :sass => [:install_ruby_prereqs, :preprocess]}.each_pair do |asset_type, prereq_tasks|
+        # This task takes arguments purely to pass them via dependencies to the preprocess task
         desc "Compile all #{asset_type} assets"
-        task asset_type => prereq_tasks do
+        task asset_type, [:system, :env] => prereq_tasks do |t, args|
             cmd = send(asset_type.to_s + "_cmd", watch=false, debug=false)
             if cmd.kind_of?(Array)
                 cmd.each {|c| sh(c)}
@@ -90,7 +92,8 @@ namespace :assets do
             end
         end
 
-        multitask :all => asset_type
+        # This task takes arguments purely to pass them via dependencies to the preprocess task
+        multitask :all, [:system, :env] => asset_type
         multitask :debug => "assets:#{asset_type}:debug"
         multitask :_watch => "assets:#{asset_type}:_watch"
 
diff --git a/rakefiles/deploy.rake b/rakelib/deploy.rake
similarity index 100%
rename from rakefiles/deploy.rake
rename to rakelib/deploy.rake
diff --git a/rakefiles/deprecated.rake b/rakelib/deprecated.rake
similarity index 100%
rename from rakefiles/deprecated.rake
rename to rakelib/deprecated.rake
diff --git a/rakefiles/django.rake b/rakelib/django.rake
similarity index 100%
rename from rakefiles/django.rake
rename to rakelib/django.rake
diff --git a/rakefiles/docs.rake b/rakelib/docs.rake
similarity index 100%
rename from rakefiles/docs.rake
rename to rakelib/docs.rake
diff --git a/rakefiles/helpers.rb b/rakelib/helpers.rb
similarity index 100%
rename from rakefiles/helpers.rb
rename to rakelib/helpers.rb
diff --git a/rakefiles/i18n.rake b/rakelib/i18n.rake
similarity index 100%
rename from rakefiles/i18n.rake
rename to rakelib/i18n.rake
diff --git a/rakefiles/jasmine.rake b/rakelib/jasmine.rake
similarity index 100%
rename from rakefiles/jasmine.rake
rename to rakelib/jasmine.rake
diff --git a/rakefiles/prereqs.rake b/rakelib/prereqs.rake
similarity index 98%
rename from rakefiles/prereqs.rake
rename to rakelib/prereqs.rake
index ff8b4b8784c0..e06d41143582 100644
--- a/rakefiles/prereqs.rake
+++ b/rakelib/prereqs.rake
@@ -1,5 +1,3 @@
-require './rakefiles/helpers.rb'
-
 PREREQS_MD5_DIR = ENV["PREREQ_CACHE_DIR"] || File.join(REPO_ROOT, '.prereqs_cache')
 
 CLOBBER.include(PREREQS_MD5_DIR)
diff --git a/rakefiles/quality.rake b/rakelib/quality.rake
similarity index 100%
rename from rakefiles/quality.rake
rename to rakelib/quality.rake
diff --git a/rakefiles/tests.rake b/rakelib/tests.rake
similarity index 100%
rename from rakefiles/tests.rake
rename to rakelib/tests.rake
diff --git a/rakefiles/workspace.rake b/rakelib/workspace.rake
similarity index 100%
rename from rakefiles/workspace.rake
rename to rakelib/workspace.rake