Implemented ScorePackageManager.edit_paper_dimensions().

The method is exposed in the score setup menu.

Example:

    Red Example Score (2013)

          build (u)
          distribution (d)
          makers (k)
          materials (m)
          segments (g)
          stylesheets (y)

          score pdf - open (pdfo)

    > p

    Red Example Score (2013) - setup

       1: title: Red Example Score
       2: tagline: for six players
       3: year: 2013
       4: catalog number: Op. 12
       5: paper dimensions: 8.5 x 11 in

    > 5

    Paper dimensions> 11 x 17 in

    Red Example Score (2013) - setup

       1: title: Red Example Score
       2: tagline: for six players
       3: year: 2013
       4: catalog number: Op. 12
       5: paper dimensions: 11 x 17 in

    >

Metadatum will be used during LaTeX source generation.