py-prefixspan: updated to 0.5.2

0.5.2
Enforce extratools>=0.8.1 to fix generator bug; Use Pipenv

0.5.1.2
Bug fix for installing on terminal without UTF-8

0.5.1.1
Tweak setup.py for support of older Python versions

0.5.1
Add custom callback function

0.5
Add FEAT algorithm for mining generator patterns

0.4
Add support for text data

0.3.6
Bug fix for referring db in custom key/filter; Tweaks

0.3.5
Refactoring

0.3.4
Remove support for no pruning in favor of upper-bound function

0.3.1
Add BIDE algorithm for mining closed pattern

(adam)