Evaluation of rules to include optional closure that can work against internal parameters of modules

[heckj]

resolves #8
resolves #19

• stub in optional evaluation closure to protocol and types
• converted rule evaluation to use ModuleSet
• simplified ModuleSet's initializers, and updated in testing
• added evalClosure to initializers for all rules, updated tests to pass in nil for full initialization
• switched out all the rules to specific typed rules, using generics - and layering over types in the LSystems
• recreated the combinatorial explosion of rewrite() methods
• fixed up the tests, although test coverage has dropped precipitously with the explosion of types
• no more "casting" of types needed in the produce closures, and they no longer accept throwing closures
• evaluation closures for parametric evaluation of rules now don't require casting either - all typed based on Rules