- made graph / txn instance unique to each gremlin instance
 - made bindings unique to each gremlin instance
 - added initial graph filter to GremlinJSPipeline constructor
 - added g.wrap and GraphWrapper to make interface more obvious
 - made g.V async, added g.VSync
 - added stubs for g.v, g.E and g.e
 - added g.query and GremlinJSQueryBuilder
 - bumped java version dep to 0.2.5