-Changed Godot exit to be clean.

-Added more debug information on memory cleanliness on exit (if run with -v)
-Fixed several memory leaks, fixes #1731, fixes #755

core/io/file_access_network.cpp

@@ -254,6 +254,7 @@ FileAccessNetworkClient::~FileAccessNetworkClient() {
 		quit=true;
 		sem->post();
 		Thread::wait_to_finish(thread);
+		memdelete(thread);
 	}
 
 	memdelete(blockrequest_mutex);