add SoftDemo examples

add example description for all examples (with word-wrap)
add the VoronoiFractureDemo, note that the collision are disabled after breaking constraints.
add optional GwenOpenGLTest, to make it easier to see Gwen user interface features.

build3/premake4.lua

@@ -130,6 +130,7 @@
 --		include "../test/hello_gtest"
 		include "../test/collision"
 		include "../test/TestBullet3OpenCL"
+		include "../test/GwenOpenGLTest"
 	end