make equality constraints work, clean up code some, don't require 'Eq' instance for solve
make equality constraints work, clean up code some, don't require 'Eq' instance for solve

darcs-hash:20070301012351-1a7c6-d00d2a90ec0f86ae5d2d6f109e24f4be72dcc589

kirbyfan64/jhc,kirbyfan64/jhc,kirbyfan64/jhc,kirbyfan64/jhc