add alias methods of Sprite#{flipped_horizontally=, flipped_vertically=}
add alias methods of Sprite#{flipped_horizontally=, flipped_vertically=}

casper91/motion-game,casper91/motion-game,HipByte/motion-game,casper91/motion-game,HipByte/motion-game,HipByte/motion-game,HipByte/motion-game,casper91/motion-game