Support the VMware Cursor Position extension on vncviewer
This change makes it possible for re-synchronizing the remote cursor on
the vncviewer when in fullscreen mode. This is done by locally moving
the cursor position to what the server thinks it should be.
Now SDL games should work!
Major restructuring of how streams work. Neither input nor output
streams are now blocking. This avoids stalling the rest of the client or
server when a peer is slow or unresponsive.
Note that this puts an extra burden on users of streams to make sure
they are allowed to do their work once the underlying transports are
ready (e.g. monitoring fds).
Provides safety against them accidentally becoming negative because
of bugs in the calculations.
Also does the same to CharArray and friends as they were strongly
connection to the stream objects.