Renamed ax_lua_check.m4 to ax_lua.m4. Updated the macro names to match the original ax_lua.m4.
Removed ax_lua_compat.m4 because it is no longer needed. Updated the README, because I forgot to do it last time.
Added a small README for the tests.
Removed AC_REQUIRE after I realized I was not using it correctly, and could not use if for my intended purpose. Macros passed to AC_REQUIRE must only be expanded through AC_REQUIRE, and not used otherwise (or else be expanded multiple times). See the AC_REQUIRE documentation for details.