This reverts commit 7cf73c94c4.
I wanted to make this better but failed so badly ;) The memory holding the thread function pointer may be freed before the thread is started, so the whole resource passing thing is needed anyway.
This probably fixes#584
* introduce ResourceOwningThread wrapper for safely passing resources
to new threads
* make CEventQueue thread-safe
* start screenshot saving thread using ResourceOwningThread
* change direct call at end of writing screenshot to thread-safe
event communication
krzys-h