Improved autoeditor menu headers.

Added (EDIT) tag to menu header when composer is editing.

Example:

    Red Example Score (2013) - materials - tempo inventory (AE)

       1: illustration.ly
       2: illustration.pdf
       3: output.py
       4: __init__.py
       5: __metadata__.py
       6: versions/

        * 8=72
        * 8=108
        * 8=90
        * 8=135

          illustration.ly - interpret (ili)
          illustration.ly - open (ilo)

          illustration.pdf - open (ipo)

          material - autoedit (ae)
          material - illustrate (i)

          output.py - check (oc)
          output.py - open (oo)
          output.py - write (ow)

    > ae

    Red Example Score (2013) - materials - tempo inventory (EDIT)

       1: 8=72
       2: 8=108
       3: 8=90
       4: 8=135

          elements - add (add)
          elements - move (mv)
          elements - remove (rm)

          done (done)

    > q