Squashed 'extensions/DFDiagram/' changes from bb52298..f659e95

f659e95 Merge commit 'a497726f3514a35ea4b72342470f9c5cc47b00bc' as 'modules/df-tileset'
a497726 Squashed 'modules/df-tileset/' content from commit 5406cfb
75cf2b5 Remove df-tileset submodule

git-subtree-dir: extensions/DFDiagram
git-subtree-split: f659e951b0ce6ca8043a7e2cdf28fe913ed1ebcb
Merge commit 'aa0fc1706d48dd07dd9f0d1b9c9b958e7ae75a70'