Lbci for Lua 5.3

[Philipp Janda <siffiejoe@...>]

Hi!

It seems that the bytecode format for Lua 5.3 hasn't changed that much 
(just a few new opcodes), and lbci for Lua 5.2 compiles and appears to 
work fine for Lua 5.3 as well. @lhf: Can you confirm this? If so, I'd 
package an updated release for LuaRocks soon.

Thx,
Philipp