Get Rid of Django!!

The purpose of this PR is to remove the project's dependencies on Django. These utils are useful for any Pythonista! It also changes the project's name from "django-instakit" to "instakit" in setup.py—I think the repo should be renamed too.

Note that I've replaced the file system stuff and am now using `os.listdir` and `__file__`. Ideally, this should probably be using pkg_resources or pkgutil instead, but that probably won't matter to many.