`pysuffix` (external dep.) needs to be ported/patched or replaced

[mromanello]

(related to #23 )

The library pysuffix is py2 only; not easy to port it to py without understanding very well what it's doing.

The library ahocorapy may be a good alternative; but perhaps others are better suited.

[mromanello]

The PySubstringSearch may do the trick here, to be tested.