Add PxFlip for sprite and tile.

[shanecelis]

Added sprite_flip.rs and tilemap_flip.rs in examples as well. The sprite_flip appears to work well. The tilemap_flip seems to work for x-axis flip but not y-axis.

I did not add any flip for text because I wasn't even sure what it might mean and it looked complicated.

[Seldom-SE]

Nice, thank you. I will take a closer look at this soon.

I did not add any flip for text because I wasn't even sure what it might mean and it looked complicated.

Fair, yeah, it's kind of a mess of math