Remove df-tileset submodule
Squashed 'modules/df-tileset/' content from commit 5406cfb

git-subtree-dir: modules/df-tileset
git-subtree-split: 5406cfbc28fdca6f55bea28a6adc95c50a71053f
Merge commit 'a497726f3514a35ea4b72342470f9c5cc47b00bc' as 'modules/df-tileset'