Merge branch 'ui-improvements' of https://github.com/nathansamson/diveclog

* 'ui-improvements' of https://github.com/nathansamson/diveclog:
  Split the dive list in columns. Columns are sortable now (name = date, depth, duration)
  Remove the redundant frames in the notebook. Closes #9
  Use a pane so the dive list can be made wider or smaller to the users wishes