* * Removed stale type declarations in parse.
* Updated parse and mg to make better use of types package.
* Added function to types package to test for valid function.
* Added function to to types package to wrap a valid FuncType as the
* most greedy of FuncType
* renamed IsFuncType and refactored to return error instead of bool. Made the return value of FuncTypeWrap more clear.
* removed unused type func declarations