work towards multi-goal rule generation

in progress, not active code.
also, corrected a typo in narration.
syntax
'New Game' button was not clearing the old game

Also has a fix for launching the program with a conflict file
More active disabling of buttons on pref screen

Prevents the user from pressing buttons at invalid times, which had the
potential to cause runtime errors.
ensure equilibria are properly recalculated

Sometimes, a change in preferences would not lead to a recalculation of
equilibria.  Now, equilibria are recalculated every time the user enters
the equilibria screen.
Basic multi-goal implemented. No GUI yet.
new GoalSeeker now powering Stability Analysis

Can show conditions for instabilty, and can show conditions for multiple
goals.