Second attempt at issue 3458. Fixes issue 3458.
Replaces all occurrences of ftell and fseek with ftello and fseeko, respectively. This matters on non-win32 where only these names are altered by the _FILE_OFFSET_BITS define. Win32 still just maps the funcs to ftelli64/fseeki64.
Also add some File::GetSize I had skipped in my last commit.
remove fifowait flag, is not needed now as we execute all events that need to be executed even if the cpu is waiting for the fifo.
this way fifo will not avid other thread events to bi executed.
Rodolfo and Me fixed ProcessFifoWaitEvents() in CoreTiming, now process the all events and not only the first :P