WIP: Make curl thread code robust and flexible.

Conflicts:

	indra/llmessage/llcurl.cpp
	indra/llmessage/llcurl.h
	indra/newview/app_settings/settings.xml
	indra/newview/llappviewer.cpp
	indra/newview/llmeshrepository.cpp

Resolved:

	indra/llmessage/llcurl.cpp:

	  Basically removed (not used anyway)

	indra/llmessage/llcurl.h:

	  Basically removed (just includes aiculr.h now)

	indra/newview/app_settings/settings.xml:

	  CurlUseMultipleThreads was remvoved.
	  CurlMaximumNumberOfHandles and CurlRequestTimeOut
	  are still in there, but unused at the moment.

	indra/newview/llappviewer.cpp:

	  CurlMaximumNumberOfHandles and CurlRequestTimeOut
	  are unused at the moment.

	indra/newview/llmeshrepository.cpp:

	  Lock mSignal always (is unlocked inside wait()).
	  Use mSignal lock to see if we are waiting; remove mWaiting.
	  Return false from the MeshFetch functions iff we have to retry
	  a HTTP fetch. Catch the error exception thrown by getByteRange
	  instead of using it's return value (always returns true
	  anyway).

indra/llcommon/llerrorthread.cpp

@@ -194,17 +194,17 @@ void LLErrorThread::run()
 	if (LLApp::isError())
 	{
 		// The app is in an error state, run the application's error handler.
-		//llinfos << "thread_error - An error has occurred, running error callback!" << llendl;
+		Dout(dc::notice, "thread_error - An error has occurred, running error callback!");
 		// Run the error handling callback
 		LLApp::runErrorHandler();
 	}
 	else
 	{
 		// Everything is okay, a clean exit.
-		//llinfos << "thread_error - Application exited cleanly" << llendl;
+		Dout(dc::notice, "thread_error - Application exited cleanly");
 	}
 	
-	//llinfos << "thread_error - Exiting" << llendl;
+	Dout(dc::notice, "thread_error - Exiting");
 	LLApp::sErrorThreadRunning = FALSE;
 }