Updating to Java8 syntax and sugar, involving:

- Making MonadicFunction and friends interfaces with default methods, annotated with @FunctionalInterface
- More authentic currying between Mon/Dy/Tri-adicFunction derivatives with default methods and paramterization
- Due to better currying through more natural apply() variants, dropping Mon/Dy/Tri-adicFunction#partial
- Using lambda syntax and method references where possible
- Replacing redundant parameter declarations with diamond notation
- Updating the pom/README
- Adding #uncurry to DyF/TriF
- Removing redundant public modifier from interface methods
- Adding more test coverage for partial application of TriF