Develop support for, or a workaround to automatically reload vertices/edges

[Sridhar Ramachandran]

(Request from user)

Bitsy doesn't allow a vertex/edge to be accessed outside the transaction. But this is something that OrientDB and Titan support.

[Sridhar Ramachandran]

Added BitsyAutoReloadingGraph that wraps around a BitsyGraph to automatically reload vertices and edges.

Changes: https://bitbucket.org/lambdazen/bitsy/commits/4b24dddb808407abba5043a2e07c50751a6b3efa