Downloads - remove debug code writing parts to files
Downloads - Accessing temporary files in children, race condition fixed.

When file not found/etc error happen, it can mean Temp file deleted by another process (in DESTRUCTOR), so we
don't need to throw error, most likelly signal will arrive in a few milliseconds.
Downloads - signal handling fixes

We don't need send SIGUSR1 to parent, it will receive SIGCHLD in any way.
Also apperantly while(wait() )helps prevent segfaults/panic