Merge add colors into constructor of gradient pattern. Since we also define color stops for gradient pattern and rear change it, mbe_pattern_add_color_stop_rgba() is merged into mb_pattern_create_radial() and mb_pattern_create_linear(). It also makes porting to graphic engines easier.

include_HEADERS = 	\
	mb_config.h	\
	mb_animate.h 	\
	mb.h	 	\
	mb_timer.h 	\
	mb_types.h 	\
	mb_observer.h	\
	mb_paint.h	\
	mb_redraw_man.h	\
	mb_shapes.h	\
	mb_tools.h	\
	mb_prop.h	\
	mb_X_supp.h	\
	mb_img_ldr.h    \
	mb_af.h         \
	mb_ani_menu.h \
	mbbutton.h      \
	mb_so.h