1. Normally when a process exits when a stream is paused, I delayed the exit propagation until resume was called, so data was not lost. However, if no data was read, resume may not get called, causing the descriptor to continually trigger the event loop. For example, if the user explicity killed the process, resume won't get triggered after the fact.
2. If the above descriptor continually triggers the event loop, other descriptors will not get serviced, which can cause a stall
3. The above two issues caused KVM issues on windows, where it would not clean up properly and leak handles because the exit wasn't gettign called. But at the same time there's a race condition depending on where in the event list the descriptor is, could cause future KVM sessions to stall.
2. Updated So that before readableStream and 'exit' are dispatched, APC's are unrolled if 'select' was interrupted, preventing stack corruption caused by trying to make a re-entrant winsock call, which is not supported by winsock.
Added ability to spawn process with specific user, under linux
Fixed edge case memory leak caused when we were trying to QueueUserAPC to a thread we were already on, which also caused a 3 second delay.
Changed WindowsRunLoop, to detect bad HANDLEs, and event an error on them, and remove them from list
Fixed linux bug, where a spawned child called 'exit' instead of '_exit' in an error condition