Modified ProgressBar() module to display output to a console or iPython notebook, depending on an input 'interactive argument.'
Included a percentage descriptor on the left of the progress bar.
Moved IPython widget/display import commands to ProgressBar.__init__, to be executed only if interactive mode is selected.
Removed test comments in ProgressBar.update_interactive().
1. Made update_console() and update_interactive() methods transparent. 2. Changed _pb attribute to _widget for clarity. 3. Removed redundant check for widget attribute instance. 4. Moved widget module imports to _update_interactive(). 5. Formatted ONLY percentage output of interactive progress bar.
Added the handling of value=None within _update_console().
Added value=None logic in update() method; not currently functioning.
Added value=None logic to update method. However, new issue has popped up; no progress bar animation in either console or interactive views in the Notebook.
Several fixes to __init__, update, _update_console and _update_interactive methods and modules.
Minor PEP8 fixes.
astropy/utils/console.py updates to ProgressBar() iPython implementation [#2789].
Fix some typos
Fix crash.  Document arguments.  Rename interactive -> ipython_widget
Merge branch 'issue_2658'