Word Enrichment: Computing in a separate thread (with ConcurrentMixin)

[PrimozGodec]

Issue

#221

Description of changes

Besides implementing the thread computation with ConcurrentWidgetMixin which fixes #221, this PR also:

• implements input and output info in a status bar
• adds better unit tests for a widget
• refactors a code a bit

Includes

• Code changes
• Tests
• Documentation

[codecov-io]

Codecov Report

Merging #492 into master will decrease coverage by 0.59%.
The diff coverage is 87.71%.

@@            Coverage Diff            @@
##           master     #492     +/-   ##
=========================================
- Coverage   63.08%   62.48%   -0.6%     
=========================================
  Files          59       59             
  Lines        6279     6243     -36     
  Branches      824      814     -10     
=========================================
- Hits         3961     3901     -60     
- Misses       2180     2208     +28     
+ Partials      138      134      -4

[ajdapretnar]

This a great PR. But I wouldn't be me if I didn't have any comments. 😬
Cluster words and Selected words is not clear to me. Cluster words apparently are all words and selected are non-zero ones (so those that actually exist in the subset). I think it would make more sense to say 'Total words' and 'Words in subset' or sth similar. Or perhaps get rid of Cluster words?

I am slightly confused by '18 words on the output'. The tooltip then explains that 18 words have been found, but do we have another widget that shows computational results instead of the output? I could be confusing for the users.

On the same note: tree (i.e. found words) should not be selectable. It can confuse the user, too.

[ajdapretnar]

Perhaps a solution for the status bar would be introducing a new icon that would replace the output icon (say a lightbulb) and signify the result of the widget.

[PrimozGodec]

I change texts and disabled the selection.

Perhaps a solution for the status bar would be introducing a new icon that would replace the output icon (say a lightbulb) and signify the result of the widget.

I will wait until we decide whether we implement this.

[PrimozGodec]

It should be finished now. @ajdapretnar can you check when you have time.