Multi-monitor window positioning is unintuitive

While I can confirm that PyRoom works perfectly well on my multi-monitor setup, I almost filed a bug report about it only working on my first (left-hand) monitor. (I'm used to having reference materials (eg. plot outlines) on the left monitor and the document on the right-hand one.)

It was only when I read the source in preparation for offering a patch that realized it could be started on my right-hand monitor.

It'd probably be best if the following behaviour were used:
1. On first run, it defaults to the monitor containing your mouse cursor (current behaviour)
2. On subsequent runs, it remembers the last position.
3. A keyboard shortcut is provided to cycle PyRoom from monitor to monitor. (I can think of no meaningful way to configure monitor selection in the preferences dialog and some people may want to be able to have two screenfuls of reference materials and flip PyRoom back and forth between their monitors as needed to uncover the materials they're currently working on)

Here's the suggested algorithm (using your variable names) for implementing the cycling:
new_monitor_number = (screen.get_monitor_at_window(self.window) + 1) % screen.get_n_monitors()

I'd give you a full patch, but I'm a little puzzled by how you set the geometry on self.window in the first place and I've already spent half the week procrastinating some boring business ethics reading.