Merge pull request #15 from mapzen/dwn

Add EdgeStatus with unit tests
added new aabb2 test
added const to Equality operator and fixed constructor bug
added tests for aabb2
fix tab issue
merged from master and added aabb2 test to ignore.
Merge pull request #17 from mapzen/gk

Gk
added aabbll test
Merge pull request #18 from mapzen/gk

added aabbll test
Fixed call to TryEquality
Merge pull request #19 from mapzen/gdg

Fixed call to TryEquality
Add EdgeLabel class for keeping cost/predecessor info during A*. Add
pbfgraphbuilder for testing.