Blender Git Loki

GPencil Drawing: Support for drawing filled strokes

It is now possible for the insides (i.e. the region contained within the stroke)
Grease Pencil strokes to be drawn "filled". This initial implementation is quite
crude.

Main Limitations:
- It uses OpenGL polygons for rendering. The main thing to be aware of with this
is that it *DOES NOT HANDLE CONCAVE* strokes too well. That is, it will just
plaster over the concave regions, which may not be what you really want

- Fills are currently turned on/off using the opacity settings. Whether we continue
doing this remains to be seen...