add sparse tracker
Merge branch 'master' of github.com:dietzc/TrackMate

Conflicts:
	src/main/java/fiji/plugin/trackmate/tracking/sparselap/SparseLAPFrameToFrameTracker.java
	src/main/java/fiji/plugin/trackmate/tracking/sparselap/SparseLAPSegmentTracker.java
	src/main/java/fiji/plugin/trackmate/tracking/sparselap/SparseLAPTracker.java