Updated patches for Lua 5.2.1

[Reuben Thomas <rrt@...>]

I've updated two of my power patches for Lua 5.2.1:

http://lua-users.org/wiki/LuaPowerPatches

Specifically, that which uses sigaction for signal handling, and that
which saves the readline history.

-- 
http://rrt.sc3d.org