Feature/mongo 2.6.5 dependencies

depsToProjection -> DepsTracker::toProjection
parseDeps -> DepsTracker::toParsedDeps
documentFromJsonWithDeps -> ParsedDeps::extractFields
Original has this here: `dassert(isNeeded.getType() == Object);` so this should maybe be something like `if(isNeeded instanceof Object) throw new Error("dassert failure");` instead.