removed one comment and added SIPL_USE_GTK check on compilation of tests
Merge branch 'unstable' of github.com:smistad/Tube-Segmentation-Framework into unstable

Conflicts:
	tube-segmentation.cpp
Updated OCL utilties to mac_compilation_2 branch
fixed bug in tube validation: one volume was not initialized
Merge branch 'unstable' of github.com:smistad/Tube-Segmentation-Framework into unstable
cleaned up the linkCenterpoints kernel
commented out var TDF check in linkCenterpoints kernel
Lowered max-distance for PCE on synthetic vascusynth data giving much better result
increased max radius on tube validation to 4 voxels
added some code for pce loop removal
wrote removeLoops function for PCE
fixed bug in MST with edges being removed before added to queue
cleaned up some code and added missing nodes to graph
loop removal working
removed some couts
fixed problem of multiple roots on the centerline
added the loop removal option
PCE now performs loop removal on CPU if this parameter or centerline-vtk-file is specified, otherwise loop removal is not performed at all
adjusted parameters of synthetic vascusynth for loop removal
added the timer-total option