tmTheme Support

This adds basic support for tmThemes files.
- The theme name is hardcoded and loaded form the AppDelegate. I will replace this soon with a way to change the theme in the settings.
- Themes are in the main bundle for now.
- This is only implemented for the Javascript language as a proof of concept. Let me know if you want to merge this and I'll add the other languages.
- This breaks one feature (that I deleted) : the background color changing on window focus change which is not defined in tmThemes.

Please see http://manual.macromates.com/en/language_grammars.html #1.4 Naming Conventions for more infos. The file format is just a regular plist file.

I've included the tomorrow theme from https://github.com/chriskempson/tomorrow-theme but they are MIT licensed so we may need to remove them.