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/llcaphttpsender.cpp

@@ -50,5 +50,5 @@ void LLCapHTTPSender::send(const LLHost& host, const std::string& message,
 	LLSD llsd;
 	llsd["message"] = message;
 	llsd["body"] = body;
-	LLHTTPClient::post4(mCap, llsd, response);
+	LLHTTPClient::post(mCap, llsd, response);
 }