Log Message:
Updated package to latest version, 1.7.1. Changes include:

1.7.1 (19-Oct-2016)

* Fix Re_str.global_replace (#132)

1.7.0 (18-Sep-2016)

* Fix stack overflow in Re_str.full_split
* Use correct exceptions in Re_str group functions
* Add experimental Re.witness
* Add experimental Re.Group.nb_groups

1.6.1 (20-Jun-2016)

* Fix Re.pp (#101)
* Add Re.Group.pp (#102)