Modifications made to the lua-5.1 sources:


1. Added the LUA_CALLINSINDEX global table @ -10001
- fast method for looking up functions using numerical indices
  (especially when using multiple lua envs that expect to use
   the same set of call-ins)
- not exposed directly to the lua code
- avoids a name lookup into LUA_GLOBALS
- avoids a double lookup into LUA_REGISTRYINDEX


2. Added:
   'int   lua_setuserdataextra(lua_State* L, int idx, void* extra)'
   'void* lua_getuserdataextra(lua_State* L, int idx)'
- faster userdata type checks
- used to avoid luaL_checkudata() LUA_REGISTRY lookups
- usually used with:  'static const char* typeName;'  pointers
- extra defaults to NULL, and lua_getuserdataextra() returns NULL
  if the object at the idx location is not a userdata object.


3. Added:
   'typedef unsigned int lua_Hash'
   'lua_Hash lua_calchash(const char* s, size_t l)'
   'void lua_pushhstring(lua_State *L, lua_Hash h, const char *s, size_t l)'
   'const char* lua_tohstring(lua_State *L, size_t* len, lua_Hash* hash)'
- precalculated string hashes


4. Applied:
   '__usedindex' patch  (with a little cleanup)

5. Added:
   '__rawset' metatag, applies to rawset(), and several table.xxx() calls