TODOs for v2:

* speed up grid manager somehow
* store descriptions in branches and ss; be able to select branches or
  ss and perform operations on them:
  + see description
  + delete version/branch
  + merge
* rewrite in ceylon
* customizations:
  + selected/unselected colors for ss, branch boxes, and lines
  + ghost item color
  + fonts for feature boxes, snapshots
  + printer stuff
    - page size
    - destination
    - orientation
    - pageanchor/offsets
  + tree spread. the larger the number, the more vertical it will be (the d
    is GridMgr.need {})
  + cell size