Silence "undefined flag: VERSION" warnings from makeinfo.

doc/mudcore.texi: Fix.
Move to Lua 5.2.

configure.ac: Search for Lua 5.2 instead of 5.1.
src/lua_api.c: Lua 5.2 fixes.
src/lua_descriptor.c: Ditto.
src/lua_log.c: Ditto.
src/lua_timer.c: Ditto.
src/lua_zmq.c: Ditto.
.gitignore everything under log/ .

.gitignore: Do this.