Code clean up.

* Removed LLCurlRequest and replaced it's last usage with LLHTTPClient API calls.
* Deleted dead code.
* Renamed all the get4/post4/put4/getByteRange4 etc, back to their
  original name without the '4'.

indra/newview/llviewerstats.cpp

@@ -878,6 +878,6 @@ void send_stats()
 	body["MinimalSkin"] = false;
 	
 	LLViewerStats::getInstance()->addToMessage(body);
-	LLHTTPClient::post4(url, body, new ViewerStatsResponder);
+	LLHTTPClient::post(url, body, new ViewerStatsResponder);
 }