Add Interpreter Tests

[flofriday]

• [x] Assignments
• [x] Built in functions
• [x] Built in operators
• [x] Built in methods
• [x] Controll flow
• [x] Nil usages
• [x] Classes
• [x] Inheritance
• [x] Lists
• [x] Tuples
• [x] Dicts
• [x] Functions
• [x] Operators
• [x] Panics

[flofriday]

There are now enough interpereter tests