Using a solid color texture instead of introducing a new filling mode.

Shapes can have a fill style type called solid fill(0x0).This
causes trouble for batching.We can eliminate this by creating a 1x1
texture of the fill color.
Add a log method for neat debug
neater log
bug fix

A silly bug, the last batch is not rendered correct! (Because FPS is
rendered before the rener state ends, and the last batch is flushed.)
updated todo list