Zach/sort vars formatting

[ZachJHansen]

Implementing an order on variables (alphabetical w.r.t. names) so quantifications are printed the same way even if they were assembled from an unordered set of variables (as is often the case in tau*)

[teiesti]

I strongly object this change as you resolve an issue in formatting that really should be resolved in the syntax tree itself. I believe that formatting should create a string representation that is as close to the syntax tree as possible. So, if you want to have the variables sorted, you really should make sure that they are sorted in the syntax tree.