- cleaned up GremlinJSPipeline constructor
 - made .V and .E synchronous pipeline operations
 - added async hasNext, next and toJSON
 - added g.wrap and GraphWrapper to make interface more obvious
 - added g.query and QueryWrapper
 - made main export a function taking in options to configure Java runtime
 - made except / retain check against the actual Collection interface
 - removed unnecesary helper methods from GremlinJSPipeline