record identifying information with each experiment

[davidsj]

This makes it easier to keep track of experiment configuration and parameters automatically. Note that "git diff HEAD" will include both staged and unstaged changes.

Example:

~/dqn/test-runs/version_info_10-02-07-56-18_0p00025_0p99$ cat cmdline 
./run_nature.py --experiment-prefix /home/dsj/dqn/test-runs/version_info --rom breakout
~/dqn/test-runs/version_info_10-02-07-56-18_0p00025_0p99$ cat git-rev-parse 
71061e912c138c1a00bac65e41d15634e14f0585
~/dqn/test-runs/version_info_10-02-07-56-18_0p00025_0p99$ cat git-diff 
diff --git a/deep_q_rl/ale_agent.py b/deep_q_rl/ale_agent.py
index fc3b04b..ea0f5a8 100755
--- a/deep_q_rl/ale_agent.py
+++ b/deep_q_rl/ale_agent.py
@@ -57,8 +57,6 @@ class NeuralAgent(object):
             f.write('\n')
         with open(os.path.join(self.exp_dir, 'git-rev-parse'), 'w') as f:
             f.write(subprocess.check_output(['git', 'rev-parse', 'HEAD']))
-        with open(os.path.join(self.exp_dir, 'git-status'), 'w') as f:
-            f.write(subprocess.check_output(['git', 'status']))
         with open(os.path.join(self.exp_dir, 'git-diff'), 'w') as f:
             f.write(subprocess.check_output(['git', 'diff', 'HEAD']))

[spragunr]

This is a good idea, but it's duplicating some of the functionality from PR #44 against the dev branch.

I've been trying to confine code changes that involve significant reorganizations or changes to the interface to the dev branch, only updating the master branch directly if there is an important bug-fix or other non-disruptive change. That's fallen by the wayside a bit as there have been a stream of critical improvements going directly into master, and I haven't had the resources to vet and merge the changes in dev. I'll merge PR #44 as soon as the author fixes some minor issues with it. Maybe at that point you could re-target this against dev with just the git version stuff?