* create new file lua_polyobjlib.c
* made a stub LUA_PolyObjLib function
* added META_POLYOBJ to lua_libs.h
* updated makefile, CMake and MSVC project files for lua_polyobjlib.c

* Array of 8 INT32's natively embedded into savedata (net and SP)!
* Initialised to zero whenever a new save (or equivalent) is started, otherwise untouched by the base game.
* Requires reservation to avoid clobber-conflicts.
    * Access via `reserveLuabanks()` - returns a read-write userdata.
    * Assign userdata to local variable or global rawset to use later.

Mostly for future SUGOIlikes, but I'm sure someone could figure out an unrelated usage eventually.

SRB2's built-in action types will now all be pushed as META_ACTION, state_t.action can be assigned META_ACTION and return it

getUserdataType returns "action" for META_ACTION variables

To re-enable support for the above, uncomment the define HAVE_LUA_SEGS line in lua_script.h. Plain bbox userdata stuff is not disabled (though currently it's not used anyway)

my P_SearchBlockmap_* functions are now a single searchBlockmap function, you can choose between "objects" and "lines" with the first arg to decide what to iterate through. I also rearranged the argument order a bit for easy stack cleanup etc

I'll remove the old stuff later, don't worry, it's disabled for now

Still some issues with node.bbox, but the rest seems to work

segs[i] is the segs table, "for seg in segs.iterate" iterates through segs, you know the drill by now I hope

(no actual SLOC changes)

Warning: Incomplete. Very prone to crashing and I might not have handled some things properly. Use with caution.

Starting work for getting sector.lines in Lua: it WORKS at the least, but I have no way to determine the size of the array itself as of yet