Attempt to add Titan indexes
Support Vertex unique indexed keys for Titan database

Add TitanGraphClient class
Move IndexCreator methods to graph client classes, remove class.
Merge branch 'indexes' into develop
Add methods to Property class, add StringProperty class

Update the way Titan client retrieves data type.
Vertex $type key is now automatically indexed as well
Add some tests for properties, remove some console.log
Merge branch 'develop'
Bump to v0.0.1