BRING BACK THE Q_MARK!!!! campaign ;) Fix the ?? instead of just blatantly deleting it, and we can decide later whether we really want to remove it.

Conflicts:
	libwccl/parser/grammar.g

For example, it can now be used in Conditional, which is done as well.

Introducing base abstract class FunctionalOperator and template Operator<T> for a functional operator returning given type of Value. Assortment of copy methods and apply methods.

Intended as a base class for library-user-level operators and rules. Allows manipulation of Variables via get, set. Intoduces cloning support.

Doesn't hurt and can help.