Add support for tile flip flags

[InnocentusLime]

Synposis

Current macroquad_tiled implementation lookups the tileset for a tile by searching via this predicate

tile >= tileset.firstgid && tile < tileset.firstgid + tileset.tilecount

before then converting from GID to a tileset-local ID. This is not entirely correct, because the GID is also used to store tile flip flags (https://doc.mapeditor.org/en/stable/reference/global-tile-ids/#tile-flipping).

This causes the above check to fail and all flipped tiles get filtered off.

What has been done

• When looking up the tileset the tile flip flags are masked off
• Since exposing the raw tile id will be backwards-incompatible they are masked off when constructing the Tile struct
• 3 new fields have been added to Tile

Notes

• I HAVE NOT updated the rendering code, but can if requested
• I have done small local testing and the fix seems to work for me

[not-fl3]

Thanks for PR!