Some enhancements to mpl polycollection support

Now supporting edgecolors, linewidth, linestyle and alpha...
I have uploaded the poly mpl example to show some of those things... and it look weird, but nice...

![polynew](https://cloud.githubusercontent.com/assets/1640669/2582349/e210eec0-b9c3-11e3-9449-ab12ec021b46.png)