Verbosity in the VIS API

[mikewinters]

Running the VIS API does not give any user feedback on the states of the code. For example:

wm = WorkflowManager('../Beethoven String Quartet #1.mid')
wm.load('pieces')
wm.run('intervals')
wm.export('CSV','output_filename')

Leaves me hanging for a few minutes without telling me what's happening.

I would suggest a verbosity 'switch' that the user can turn on or off, but which causes VIS to systematically post what it is doing. This is done with a global control in the MIRToolbox, and it works great!

[crantila]

This will be a change to the WorkflowManager.

I think we could implement this with a single "update status" method. All the other methods will call _update_status() when applicable, and the latter will act in a way suitable for the interface available. By default, probably that's just a print statement, but the PyQt interface could change this to emit a signal.

Whether any status messages do anything can be controlled by a Shared Setting.

[alexandermorgan]

Motion to close... I don't think we need this.

[crantila]

Closed in favour of #357, which seems more suitable for the framework's goals today.