Further header cleanup and a few updates

Updated llstring to current linden
Further linden_common cleanup
Header cleanup
Raised banlines to 5000 as per linden server change
Included missing llmediaentry.cpp file
Minor whitespace changes here and there

indra/llmessage/lldispatcher.cpp

@@ -29,7 +29,6 @@
 #include "lldispatcher.h"
 
 #include <algorithm>
-#include <iterator>
 #include "llstl.h"
 #include "message.h"