Expand solution check and allow input for alpha and beta #6

As of now the input for alpha and beta values are omitted though they are shown in the solution animation. I'd suggest that an input of those values should be allowed so the user can validate whether he or she understood the whole algorithm and not only found a solution.

Furthermore the solution check does not apply to cutting of trees or in other words it does not check whether the user did cut off the correct trees or left one. This can easily be reproduced via valid solution for a tree which cuts of the first branches. Pressing the solution button again will not show any message regarding cut offs.