move tests dir inside openelex package
add MongoTestCase for db-dependent test cases
fix path bug in StateCache class
path fix in StateBase and some whitespace tweaks
update mongo connection handling

Added Mongo prod connection initialize to StateBase, which
should be inherited by any base classes that interact with the db.

Removed mongo connection instantiation code from settings/models
to support different connection configs for testing vs production.
doc tweak
fix import bug
Merge branch 'dev' of github.com:openelections/core into dev