- wrote a function in SimpleFormulaChecker.hs that can be used to evaluate (for now just preconditions) in java files;
- wrote some (for now) very basic tests for LExpr eval;
- worked on QuickCheck.hs, but I have some ideas (mainly regarding arrays) that I need to discuss before I proceed;
- added extra parentheses in Pretty.hs to make debugging the AST easier.

#15

does not actually work though

Closes #13

closes #10