Implement xflip/yflip/rotation flags in tilemap layers

[dacap]

A task from #977 is the implementation of xflip/yflip/rotation flags for each individual tile instance in the tilemap. This is something planned in the .aseprite format in Cel chunks:

• For cel type = 3 (Compressed Tilemap)
  WORD Width in number of tiles
  WORD Height in number of tiles
  WORD Bits per tile (at the moment it's always 32-bit per tile)
  DWORD Bitmask for tile ID (e.g. 0x1fffffff for 32-bit tiles)
  DWORD Bitmask for X flip
  DWORD Bitmask for Y flip
  DWORD Bitmask for 90CW rotation
  BYTE[10] Reserved
  TILE[] Row by row, from top to bottom tile by tile
  compressed with ZLIB method (see NOTE.3)

https://github.com/aseprite/aseprite/blob/main/docs/ase-file-specs.md#cel-chunk-0x2005

This issue was created so some users can keep track/subscribe to the implementation of this feature.

[dacap]

Now we can flip/rotate tiles using Space+X or Space+H (flip horizontally), Space+Y or Space+V (flip vertically), Space+D (flip diagonally), Space+R (rotate).

We can also enable automatic match of flipped tiles when we create a new tileset or change a tileset properties: