nubz4lif

Results 3 issues of nubz4lif

With both [Baritone](https://github.com/cabaletta/baritone) and bobby installed, if you have a world named bobby-fallback in your saves, the game lags heavily in Multiplayer. Tested this without any mods except Baritone and...

Adds support for [Feral Gamemode](https://github.com/FeralInteractive/gamemode) gamemode_client.h is taken from [here in their repo](https://github.com/FeralInteractive/gamemode/blob/master/lib/gamemode_client.h) Gamemode automatically can re-nice processes, or run scripts when turned on/off

reviewing-internally

Currently the game will immediately close after loading on Linux builds, but the newest version of hxCodec fixes this Should fix #2428