0.7.0

This release contains a number of improvements and fixes, and adds support for the library of finite semigroup and monoid presentations in libsemigroups and the Stephen class from libsemigroups.

• Add functionality for the presentation helper replace_word by @MTWhyte in #84
• Out neighbours for action digraphs by @james-d-mitchell in #91
• Add functionality for the fpsemi-examples presentations by @MTWhyte in #85
• Stephen by @james-d-mitchell in #93