Add virtualenv directory to gitignore
Run tests without requiring postgres.

This commit allows the use of sqlite3 as a backend for testing. To
test with sqlite3 simply do:

    export DB='sqlite'; python setup.py test

This also removes psycopg2 from the test_require list, and moves it as
an addition pre-test install for travis.
Remove django-celery dependency.
Added to contributors.
Merge pull request #26 from Wilduck/remove-djcelery-dependency

Remove djcelery dependency
Update version.py
Update setup.py
Update version.py
entity syncing uses sync for relationships and upsert
did minor optimizations to entity syncing
bumped version
Merge pull request #29 from wesleykendall/feature/optimize

Feature/optimize
added entity registry and entity config model
added basic entity registry tests
updated entity registration tests
tested register decorator
entities are registered new way in models
entity registry works with previous tests
changed how the entity registry stores information
num queries went down a lot with optimizations