Remove trivial container/list usage
Remove uses of container/list
fix gremlin documentation for In and Both

this was likely a copy/paste from Out.
feel free to change the wording to fit your style.
Fix #21 and change the MQL semantics slightly to match the original MQL
Add test for semantics from #21
Replace string type with graph.Direction

This conversion is not complete as there are still uses of string
directions via the Direction.String method in leveldb.
Retain correct copyright notice
Move iterators into separate package

Also reduce API exposure and use standard library more - and fix bugs I
previously introduces in mongo.
Cleaning and TODOs
Remove dead var
Remove redundant loggin functions
Fix symlink for following the instructions