Updating travis.yml and fixes for Django 1.7
Merge pull request #6 from waveaccounting/try-stuff-on-travis

Updating travis.yml and fixes for Django 1.7
Bumping version and uploading to PyPI.
Add support for url and modified_time
Merge pull request #4 from pipermerriam/piper/add-url-and-modified-time-support

Add support modified_time, created_time, and accessed_time
Bumping version, adding CONTRIBUTORS
Updating CONTRIBUTORS with past names
Use bytes as default file content type.

This is a workaround for the case when `InMemoryStorage._save()` gets
passed bytes as the `content` argument, but the file was already created
with `StringIO` as an underlying stream class. (`InMemoryFile.__init__`
determines stream class by looking at `content` type.)