Implemented avoid_crossing_perimeters with VisiLibity
Update MANIFEST and test
Merge branch 'master' into visilibity

Conflicts:
	lib/Slic3r/GCode.pm
	xs/MANIFEST
Fix MANIFEST
Simplify islands before initializing MotionPlanner
New implementation of Avoid crossing perimeters using Voronoi diagrams
Merge branch 'acp-voronoi'

Conflicts:
	xs/xsp/my.map