enable d2d factory with multi-thread support. no crash now with the same
logic as renderers

TODO: compare cpu usage with single thread with manual lock
video quality support for gl, d2d and qpainter

TODO:
1. more levels? opengl has many combinations. d2d has 4 levels
2. move setupQuality() to handlePaintEvent()
3. gdi+, xv
4. text quality api
5. keep last renderer's quality when renderer changed
6. MIPMAP?