Add Lemuroid: a libretro based multi-emulator for many consoles.

Hi,

with this pull request I'd like to add Lemuroid to f-droid repository. I followed your guides and the application correctly builds.

This application is entirely free software, but it downloads pre-compiled libretro binaries from https://buildbot.libretro.com/ and dynamically loads them. These cores are all open-source, but maybe an appropriate AntiFeature is needed.

Feel free to let me know if there is something I missed or needs changing.

Closes rfp#1351 (closed)