Add dev command to run in native envs.

[auraz]

I have some issues with paver, local Mac OS dev env.

1. when i do
   paver run_all_servers --settings=dev --worker_settings=celery
   Ctrl-C
   and
   paver run_all_servers --settings=dev --worker_settings=celery
   second time
   I got

0 errors found
Django version 1.4.8, using settings 'cms.envs.dev'
Development server is running at http://0.0.0.0:8001/
Quit the server with CONTROL-C.
Error: [Errno 48] Address already in use
0 errors found
Django version 1.4.8, using settings 'lms.envs.dev'
Development server is running at http://0.0.0.0:8000/
Quit the server with CONTROL-C.
Error: [Errno 48] Address already in use

2. If in one terminal window I do
   paver studio --settings=dev
   and in second terminal window I do
   paver lms --settings=cms.dev
   In 1st terminal process is aborted with next message:

0 errors found
Django version 1.4.8, using settings 'cms.envs.dev'
Development server is running at http://0.0.0.0:8001/
Quit the server with CONTROL-C.
  overwrite lms/static/sass/application-extend1.css
  overwrite lms/static/sass/application-extend2.css
  overwrite lms/static/sass/application.css
  overwrite lms/static/sass/course.css
    CHANGED: /Users/kry/mitx_all/edx-platform/lms/static/sass/application-extend1.scss
sass --style compressed --cache-location /tmp/sass-cache --load-path ./common/static/sass --update -E utf-8 */static
Processes ending

And vice versa.

@singingwolfboy please review.

[singingwolfboy]

I'm not clear on how this pull request solves your two problems here. For the first problem, looks like you want to fix paver's run_all_servers command, so that hitting ctrl-C will correctly stop the servers. git blame says that @wedaly wrote that code -- @wedaly, can you take a look at this?

I'm not sure what's going on with your second problem -- sounds like the second process is killing the first process. Can you track down what's causing that?

Either way, I don't think that adding another paver task is the right solution to this problem.

[auraz]

This PR solves 3rd problem: allow run LMS and Studio in dev env.

2nd problem - have no idea how I can track it down.

[singingwolfboy]

@auraz instead of creating a new paver task, can you modify the existing run_all_servers task?

[auraz]

@singingwolfboy Done, please continue review.

[singingwolfboy]

Rather than --settings and --lms, I feel like a more intuitive interface would be:

• --settings: set both lms and cms
• --settings-cms: set cms only, overriding the value from --settings (if provided)
• --settings-lms: set lms only, overriding value from --settings (if provided)

You could also make the run_all_servers task default to dev for cms and cms.dev for lms. That seems like a sensible default to me.

[auraz]

makes sense.

[auraz]

Except the last one: default worker is 'dev_with_worker' which is not suit for local env. For local env, default worker should be 'celery'

[auraz]

@singingwolfboy please continue review

[singingwolfboy]

Looks great! 👍