[RP] new buffer open on other-window

[twb]

Hi.
Maybe this is old hat, but ...

In emacs, when a new buffer is opened, it appears in the `other' pane.

My thinking is, if there is an empty pane, rp should create the window
in that, rather than the focused pane.

Useful when you have a primary window, and are creating / destroying
secondary windows (e.g. an emacs and a bunch of dillo (browser)
windows).  You can keep the primary open in one pane and refer to it
while the secondaries come and go.  

--twb