Extract location fusion engine
Move location updates into FusionEngine
Impatient while testing
Extracts mock location engine
Maintain single location engine instance at a time
Adds ability to cancel GPX trace replay when turning of mock mode
Fix demo app crashes due to null request or null trace file
Javadoc typo
Merge pull request #12 from mapzen/chuck/extract-fusion-engine

Extract FusionEngine and MockEngine to power location updates