You can now set the FPS goal with `--fps=10` (or whatever) on the command line;
and the current (measured) FPS is displayed in the lower right corner.
During the run, you can bump the FPS goal up and down with `F` and `f` respectively!
The Slipnet itself turns out to be boring to look at.
More interest is found in the Workspace structures, such as bonds,
groups, and correspondences.
The old behavior of `curses_main.py` is still accessible via
python curses_main.py abc abd xyz --focus-on-slipnet
This isn't terribly useful to the human observer, actually.
It seems like the most useful factors that ought to be displayed
are really the groups/bonds in the workspace and the current
"rule" (if any). Particularly, with the current design of Copycat,
it seems like the "rule" should be part of the displayed output
just the same as the modified target string.
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.
