Add a curses front-end. This is looking good now!

And clean up some logic in `rule.py`. This is the place where the
"brains" of Copycat really live, it seems; Copycat can only succeed
at solving a puzzle if it can take the `Rule` it deduced and apply
it to the target string to produce a new string. And it can only
do that if the necessary *actions* have been programmed into `rule.py`.
Right now, it explicitly can't deal with "rules" that involve more
than one local change; that involve reversal; or more importantly,
IIUC, rules that involve "ascending runs", because the idea of a
successor-group is(?) known to the Slipnet but not to `rule.py`;
the latter deals only in "strings", not in "workspace objects".
This seems like a major flaw in the system... but maybe I'm missing
something.

copycat/workspace.py

@@ -32,7 +32,7 @@ class Workspace(object):
         self.reset()
 
     def reset(self):
-        self.foundAnswer = False
+        self.finalAnswer = None
         self.changedObject = None
         self.objects = []
         self.structures = []