Bundles! (basic functionality) Changes made in this commit: * Added new dependencies (see pip-requirements) * Added new dependency and setup information to README * Deleted the included mptt app (in apps/mptt) in favour of just adding the dependency to pip-requirements (makes it easier to update, etc) * Changed the import convention to use `from apps.bundle.models import Bundle` rather than `from agora.apps.bundle.models import Bundle` because Celery was having problems with the latter style. Everything should still work. * Moved the syntax-highlighting and related code for snippets into separate HTML files so that they can be used by the bundle app And, of course, the ability to upload bundles. But wait! There's more! Changes still to come, for only $19.95 a month: * Bundle versioning * Automatic license integration (i.e. adding headers to files) * The ability to download bundles (zip, tar, etc) * Rating bundles * And much, much more! Batteries not included.