Fixing several minor issues

- #69: Allow destroy() to be called by user without generating messages
- #66: Remove warning in ofxBox2dBaseShape::setData()
- #65: Polygon create doesn't like 3-sided polygons
- #64: ofxBox2dPolygon::clear() calls itself
fixed small bug in ShapeTexture example.
Fixed include pathes
Fix Win32 preprocessor in triangle impl
Quickly hacked assert function ;-)
Remade Visual Studio 2012 projects
Merge pull request #77 from Mat-Loz/master

Fix issues with Visual Studio 2012
Merge pull request #70 from totalgee/minorFixes

Fixing several minor issues