Made functions instances of Functor, introduced AbsFun 1-9 as default implementation of Functor for Function 1-9
Changed Lists.java and Functions.java to use AbsFun, added curry, uncurry, and some other common help funcions to Functions.java
Some changes in the Monad generic type parameters
Added ApplicativeFunctor
Made functional lists instances of ApplicativeFunctor
Added the Maybe type