Big and almost final

Due date in 4 days, added tests, project report (not here - it has
sensitive data and will not be uploaded, but do know it exists!) ,
finished GUI, improved some functions, added assertions, make some
stuff more readable, added dynamics vars, removed scalarAdd function
since there is no reason for it - it's not really something a
matrixCalculator needs.
Added function that sets cell at a given index in a given matrix with a
numeric value. Some other stuff I can't remember, have been working all
night for a few nights.