Feature/mongo 2.6.5 dependencies

depsToProjection -> DepsTracker::toProjection
parseDeps -> DepsTracker::toParsedDeps
documentFromJsonWithDeps -> ParsedDeps::extractFields
The original source code does not `sort()`. Is that required?
Also, it's usually preferred to just use a `for(var key in obj){` loop. They're generally faster and more debugger friendly.