Add FieldLoader support for Size.
Sort asset browser list by filename.
Add limited Tmp(TS) support.

Supports basic tile data, but not z or extra data.
Support rectangular tiles.
Replace the placeholder tile.
Add three additional spawn points
Update changelog.
Fall back to square tiles for the editor.
Merge pull request #4391 from pchote/rectangular-tiles

Add support for TS terrain sprites and non-square cell sizes.