Small changes to .gitignore and install script

[codekansas]

Explanation:

• .DS_Store - Useless file created by Mac file browser
• .egg-info - Created when doing pip install
• staticfiles - Migrated staticfiles, should probably be ignored
• pip install -e . - Safer / more consistent version of python setup.py develop

I talked to @hdoupe about my regular schedule now so expect commits around this time MWF/Sat/Sun.

[hdoupe]

Thanks for the contribution @codekansas. We've always kept the staticfiles in the repo, and I was never really sure why. @GoFroggyRun is there a back-story for this? I just want to make sure that they weren't added as some Heroku work around or something.

[GoFroggyRun]

@hdoupe I'm not sure about staticfiles either: they were there before I worked on Policy Brain repo. @martinholmer had similar concern before, but we didn't get any answer from Continuum.

[hdoupe]

@GoFroggyRun Ok, thanks. I think that we should just remove them. If there's a problem for some reason, then we can add them back.

[codekansas]

@hdoupe ping

[hdoupe]

Thanks for the contribution @codekansas