Removed another source of related errors for the same type error.
Added collection wrapper class for type environment.
Whitespace
Started implementing evaluation of expressions.
Implemented evaluation of expressions.
Started on Renderer.
Question labels are shown.
Questions now show input fields.
Input fields of questions in if statements aren't shown on init.
Question labels and input fields are rendered in a container.
Removed vertical space between  questions.
Added observers. Completed functionality, some refactoring needed.
Added tests for the evaluator.
Passed valueEnv with notifyObservers() instead of saving it as a field of the observers.
Cleanup
Improved tests.