Add Shattered Pixel Dungeon and some of its forks

[gursuj]

[gursuj]

There's another FOSS game called Bombsquad but you might want to take a look at the 1st 2 questions in the FAQ to decide if it can be added to this list or not. Specifically this:

Anything not directly contained in this repository, however, even if automatically downloaded by build scripts, is still proprietary and cannot be redistributed without explicit consent. This includes assets and prebuilt libraries/binaries.

Also, the dev is still working on it and is planning to release it on consoles and Steam for the next major version.