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)

Signed-off-by: Johannes Dewender <rpm@JonnyJD.net>
Signed-off-by: Panu Matilainen <pmatilai@redhat.com>