Variable Size Regions! Support for prehash RegionSizeX and large patches. (WIP)

Mostly from Ukando, tweaked a bit to be cleaner, and a little less dramatic.

decode_patch_header now takes a bool optionally, as third argument.
_PREHASH_RegionSizeX is the only used of the two _PREHASH_RegionSize*.
llsurface.cpp: Copy the connectNeighbor for variable size regions almost directly from Ukando
llsurfacepatch.cpp: Patch code from ukando and voodoo.
Changed hardcoded 256 constants and such to width functions in: llglsandbox.cpp, llsurface.cpp, llviewerregion.cpp, llviewerparcelmanager, llviewerparcelmgr.cpp, llvowater.cpp, llworld.cpp
Use region specific width in: llagent.cpp, llglsandbox.cpp, llmanip.cpp, llmanipscale.cpp, llpanelobject.cpp, llviewerbject.cpp, llwind.cpp
Use 256 in llnetmap.cpp in places...
llfloaterregioninfo.cpp: Aurora grid has wacky textures.
Add LLViewerParcelMgr::widthUpdate() for updating mParcelsPerEdge given a region's width. Used in llstartup now.
Add LLWorld::setWidth() for getting a region's size from LLMessageSystem pointers and setting mWidth and mWidthInMeters, accordingly. Called in llviewermessage.cpp as well.

indra/newview/llworldmap.cpp

@@ -375,10 +375,25 @@ LLSimInfo* LLWorldMap::simInfoFromPosGlobal(const LLVector3d& pos_global)
 
 LLSimInfo* LLWorldMap::simInfoFromHandle(const U64 handle)
 {
-	sim_info_map_t::iterator it = mSimInfoMap.find(handle);
-	if (it != mSimInfoMap.end())
+	std::map<U64, LLSimInfo*>::const_iterator it;
+	for (it = mSimInfoMap.begin(); it != mSimInfoMap.end(); ++it)
 	{
-		return it->second;
+		const U64 hndl = (*it).first;
+		LLSimInfo* info = (*it).second;
+		if (hndl == handle)
+		{
+			return info;
+		}
+		U32 x = 0, y = 0;
+		from_region_handle(handle, &x, &y);
+		U32 checkRegionX, checkRegionY;
+		from_region_handle(hndl, &checkRegionX, &checkRegionY);
+
+		if (x >= checkRegionX && x < (checkRegionX + info->getSizeX()) &&
+			y >= checkRegionY && y < (checkRegionY + info->getSizeY()))
+		{
+			return info;
+		}
 	}
 	return NULL;
 }