add RTGUI_RESTRICT and RTGUI_PURE
declare rtgui_color_get_bpp and rtgui_color_get_bits as pure function
RTGUI: add matrix implementation

Code port and modified from ejoy2d.
add the dc_trans #1
fix matrix
implement the dc_trans
add rotate animation engine
Merge pull request #75 from grissiom/dc_trans

Dc trans