Metaproperty support for RemoteVertex; properties follow a similar
interface to gremlin properties.

New object hook for json deserializer detects elements and deserializes
them as RemoteElements, either RemoteVertex or RemoteEdge.

The RemoteElement interface is (loosely) based on tinkerpop's Element
interface.

For obvious reasons, RemoteElement should only have read-only methods
and properties.

Marked WIP for now because:

1) no tests yet :c
2) only the driver part has been implemented, but changes would need to
be made to goblin as well

added better error handling

suppress metaclass creation log for base element classes

Changed config and registry to app module. Simplified traversal API