first pass at adding lua
added lua class
erge remote-tracking branch 'origin' into lua

Conflicts:
	src/mjolnir/pbfgraphbuilder/pbfgraphbuilder.cc
added LuaTagTransform class.  Added lua parsing logic.
removed pbfgraphbuilder
Merge pull request #43 from mapzen/lua

Lua
Merge branch 'master' of https://github.com/mapzen/valhalla into gdg