Fixed set not equal.
Changed between/not-between to the more general  within/not-within
Pluggable analysis.
Updated tests.
Fixed ref to abstract class.
Improved join propagators.
Improved join function.
Improved sum set.
Negate tests.
Unsat now returns constraints instead of meaningless strings.
Version number.
Constraints are now immutable.
Updated for javascript generator.
Stronger symmetry breaking prototype.
Fixed references to abstracts.