The test suite doesn't seem to enforce behavior related to self-relating
edges. TinkerGraph does this:
gremlin> g = TinkerGraph.open().traversal()
==>graphtraversalsource[tinkergraph[vertices:0 edges:0], standard]
gremlin> g.addV().as('a').addE('self').to('a')
==>e[1][0-self->0]
gremlin> g.E()
==>e[1][0-self->0]
gremlin> g.V().bothE().count()
==>2
Should bothE() return 2 in this case or 1? I think that we've said in the
past that g.E() is the same as g.V().outE() or g.V().inE(), but not
necessarily g.V().bothE(). Thoughts?
