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/cwdebug/debug.h

@@ -118,6 +118,7 @@ extern CWD_API channel_ct sdl;
 extern CWD_API channel_ct backtrace;
 extern CWD_API channel_ct statemachine;
 extern CWD_API channel_ct caps;
+extern CWD_API channel_ct curl;
 
 #endif