PyMeshLab v0.2

Changelog:

• run filters methods directly from MeshSet (e.g. ms.convex_hull() instead of ms.apply_filter('convex_hull'))
• create new Mesh takes custom per vertex and per face quality values
• plugins that need GLContext work now
• possibility to enable cpu opengl on windows with pymeshlab.use_cpu_opengl()
• bugfix on input file parameters
• other small bugfixes and performance improvements