Export rtgui_container_get_object function.
Merge branch 'master' of https://github.com/RT-Thread/RTGUI
close the filerw in the end of function.
animation: add background dc buffer
Merge branch 'master' of https://github.com/RT-Thread/RTGUI
Fix color issue in aa_line routine.
Add _UI_ABS macro to get absolute value.
Remove the temporary buffer to reduce memory usage.