Added a thread-safe and robust wrapper for APR pools.

See http://redmine.imprudenceviewer.org/issues/590
and https://jira.secondlife.com/browse/SNOW-596

indra/test/lltemplatemessagebuilder_tut.cpp

@@ -35,7 +35,6 @@
 #include "linden_common.h"
 #include "lltut.h"
 
-#include "llapr.h"
 #include "llmessagetemplate.h"
 #include "llquaternion.h"
 #include "lltemplatemessagebuilder.h"
@@ -59,7 +58,6 @@ namespace tut
 			static bool init = false;
 			if(! init)
 			{
-				ll_init_apr();
 				const F32 circuit_heartbeat_interval=5;
 				const F32 circuit_timeout=100;