Finish lua 5.2 support, trac #865

Lua52 support was started with ac959fed0082cb253d45c7a04866e8654e962442.

Compilation tested with Lua 5.2.1 and Lua 5.1.5.

The short typerror() snippet is taken from luaL_typerror in Lua 5.1.5
(MIT license)

http://rpm.org/ticket/865