Add support LuaJIT to minetest

I know here already unaccepted pull request from BlindBanana with LuaJIT but as i know is based on original makefile and i think CMake based build system should be better and more flexible. so my request is like other option to chose from. LuaJIT 2.0.1 (with hotfix) here also. checked on win x86/x64 but sadly still unchecked on *nix.
PS. is my first pull request so sry if i do something wrong