Declare update method in MutableAssignment trait.
Remove TrueValue and FalseValue, and fix previous change to BooleanDomain.
Introduce new inner subclass BooleanDomain.CategoricalValue.
Add comments to many classes in cc.factorie.variable.
Add comments to classes in cc.factorie.optimize
Add comments to classes in cc.factorie.model
Merge branch 'master' of github.com:factorie/factorie