nighty on LuaJIT versions, a lua_shared fork and Jolt physics

In #developer-talk, nighty said the main branch uses LuaJIT 2.0.4 and the x86-64 beta uses LuaJIT 2.1 beta 3. Zaurzo added that 64-bit main uses the same LuaJIT as x86-64. nighty described his lua_shared fork: it targets a custom language but should run existing GMod Lua exactly like stock, and isn't public yet. Its threading is worker-based, with message passing between separate Lua states. He also showed Jolt physics experiments.