Improved (ck) and (ck*) output.

The method now prompts to show only unrecognized assets (default) or all
assets.

Example: Unrecognized assets only:

    Score Manager - scores (examples)

       1: Blue Example Score (2013)
       2: Étude Example Score (2013)
       3: Red Example Score (2013)

          scores - copy (cp)
          scores - new (new)
          scores - remove (rm)
          scores - rename (ren)

    > ck*
    Show only unrecognized assets? y
    Blue Example Score (2013):
        1 unrecognized file found:
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/blue_example_score/extra_file.txt
    Étude Example Score (2013):
        no unrecognized assets found.
    Red Example Score (2013):
        no unrecognized assets found.
    3 packages checked.

    >

Example: all assets:

    Score Manager - scores (examples)

       1: Blue Example Score (2013)
       2: Étude Example Score (2013)
       3: Red Example Score (2013)

          scores - copy (cp)
          scores - new (new)
          scores - remove (rm)
          scores - rename (ren)

    > ck*
    Show only unrecognized assets? n
    Blue Example Score (2013):
        6 of 6 required directories found:
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/blue_example_score/build
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/blue_example_score/distribution
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/blue_example_score/makers
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/blue_example_score/materials
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/blue_example_score/segments
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/blue_example_score/stylesheets
        2 of 2 required files found:
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/blue_example_score/__init__.py
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/blue_example_score/__metadata__.py
        1 optional directory found:
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/blue_example_score/test
        1 unrecognized file found:
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/blue_example_score/extra_file.txt
    Étude Example Score (2013):
        6 of 6 required directories found:
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/etude_example_score/build
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/etude_example_score/distribution
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/etude_example_score/makers
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/etude_example_score/materials
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/etude_example_score/segments
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/etude_example_score/stylesheets
        2 of 2 required files found:
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/etude_example_score/__init__.py
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/etude_example_score/__metadata__.py
        1 optional directory found:
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/etude_example_score/test
        no unrecognized assets found.
    Red Example Score (2013):
        6 of 6 required directories found:
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/red_example_score/build
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/red_example_score/distribution
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/red_example_score/makers
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/red_example_score/materials
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/red_example_score/segments
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/red_example_score/stylesheets
        2 of 2 required files found:
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/red_example_score/__init__.py
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/red_example_score/__metadata__.py
        1 optional directory found:
            /Users/trevorbaca/Documents/abjad/scoremanager/scores/red_example_score/test
        no unrecognized assets found.
    3 packages checked.

    >