New: Changes for Release 1.2.5

Refer to VERSION_HISTORY.md for more details.
Merge branch 'master' into new_workflow_order
Fixed: Unicode String Literals --> String Literals

We'll prepare for python 3, now that music21 made the leap!
Formatting: Refactor WorkflowManager._two_part_modules()

After Alex's revisions, I realized there are a couple of other things we
could smooth over. So, before rewriting the unit tests, I did it.
Fixed: Revise Unit Test for WorkflowManager._two_part_modules()

Accounts for part of the changes in a787a568201601216c8510855de503739d13f1f6

Working toward issue #310
Formatting: Minor Cleanup as Suggested by Pylint