Implement Piet interpreter

[kamil-adam]

Implemented Piet

• Original Piet Interpreter - Erik Schoenfelder has written npiet, a very nice Piet interpreter with the ability to print program traces and a supporting Piet editor! It's feature-packed and pretty cool.mall
• https://github.com/helvm/piet-willem-o - An interpreter for the programming language Piet (http://www.dangermouse.net/esoteric/piet.html). Currently only runs the program "hi.png".
• https://github.com/helvm/pietc - pietc is a Piet compiler. This compiles Piet programs to native executable programs.
• https://github.com/helvm/piet-interpreters - it doesn't compile

Features

• use ppm P3 and P6
• use xpm
• use llvm-pretty

Require

• Use Either, remove all error #7
• Use Functional Dependency for Memory (Stack and Ram) and fix signatures of methods (Associated Type) #37
• https://github.com/helvm/helma/issues/39