Provides a light wrapper around Lua_jll that is close to a one-to-one mapping of the Lua C API, with the following differences:

• C macros are re-implemented as Julia functions.
• Where the C API uses output arguments, the wrapper returns a tuple instead.
• Where the C API returns integer status codes, enums are used instead.
• TBD: Return errors nicely from lua_p* functions?
• Functions that appear to be pointless in the context of Julia have been omitted (e.g. lua_pushfstring).

This is a work in progress, the API is not completely mapped, and test coverage is poor.