Add license to luac.lua file
Add license to luac.lua file

This was written by @starwing who said it can be licensed the same as the rest.

https://github.com/luvit/luv/commit/7acadf23c3f61a7cdf4a279ae855ed67dca2a6fa#commitcomment-18293888
joerg-krause/luv,luvit/luv,luvit/luv,joerg-krause/luv,zhaozg/luv,zhaozg/luv