This patch adds two new painters located at gems/include/polygon_gfx.
Both painters draw convex polygons with an arbirary number of points.
The shaded-polygon painter interpolates the color and alpha values
whereas the textured-polygon painter applies a texture to the polygon.
The painters are accompanied by simplistic 3D routines located at
gems/include/nano3d/ and a corresponding example (gems/run/nano3d.run).
