Merge pull request #40 from mapzen/dwn

Add some framework for PathAlgorithm.
move test data to test directory
add the osm2pgsql and lua files for use in db imports and tagtransformations
add minimal mjolnir docs
Merge pull request #41 from mapzen/kk_lua

add lua for tagtransform and docs for db import
Get a directed edge given its index within the tile (do not need
entire graphid.
Outline of the A* algorithm. Still some missing pieces and cleanup
needed.
Add tests and get adjecency list working.
Merge remote-tracking branch 'origin/master' into dwn