Fix suffix folding

The latest version apparently broke suffix folding: for example stroking "PHOEPBD" for "moaned" with only "PHOEPB" for "moan" defined in the dictionary does not work. This branch hopefully takes care of that:

- I updated the equality implementation for the Translation class: both strokes and output must match
- I updated the tests to take that change into accounts
- I fixed suffix folding, making the associated test pass