Texfetch/cache changes:

Added SEND_UDP_REQ and	WAIT_UDP_REQ fetch states.
Parse 'content-range' from headers.
Purge 'complete' textures from the cache if they lack 'end of codestream' marker.
Added boostlevel/category to textureview display.
More diagnostic output.
Discard handling tweaks/bugfixes from v3.

indra/newview/llviewertexturelist.cpp

@@ -1466,6 +1466,7 @@ void LLViewerTextureList::processImageNotInDatabase(LLMessageSystem *msg,void **
 	LLViewerFetchedTexture* image = gTextureList.findImage( image_id );
 	if( image )
 	{
+		llwarns << "not in db" << llendl;
 		image->setIsMissingAsset();
 	}
 }