ExUnitFixtures v0.3.1

• Hid some documentation on the internals of the library from the public API docs.
• Module scoped dependencies can no longer depend on test scoped dependencies.
• Fixed an issue where fixtures were marked as "function" scoped by default, rather than the "test" scoped expected in most places and stated in the docs.
• Fixed an issue where module scoped fixtures would be created on module start, but then also created whenever a test depended on them.