Change to pytest from unittest
Split big test file into files with 1 test class.
Re-add init file to avoid test package error.
Fix comparison bug in test.

Ungilded comments have value 0 for gilded. Gilded have > 0
Simplify loops in test with first and all
Flatten and remove usage of unittest
Move getting normal testing subreddit into helper
Fix bug in image_test

The final assert creates a list of booleans. They intended to
test whether a file had been uploaded, but didn't since.
assert [False, False, False] doesn't raise an error.
Allow test functions to have longer names.
Make tests skippable where appropriate

This was impossible before because skips were first
introduced to unittest in python version 2.7 and
PRAW is designed to work with python 2.6+.