Look into opening libraries on Lua 5.1 and Luajit

[natecraddock]

The open*() functions for loading individual standard libraries for Lua 5.1 may need to be reworked. The docs say to use lua_call. https://www.lua.org/manual/5.1/manual.html#5

Same for luajit.

I found this when enabling apicheck for luajit. Opening the bit library failed with an api check error.