Summary:
Removed __pycache__
Added .gitignore to prevent upload of unnecessary files
Test Plan:
1. Change the code.
2. Compile the code.
3. Check that __pycache__ exists.
4. Check with `git status` that __pycache__ is not shown.
Reviewers: hmollercl
Reviewed By: hmollercl
Differential Revision: https://phab.lubuntu.me/D90
