* New tool Vis creates an interactive visualisation in HTML format,
  or a bare Vega graph spec (JSON format). The user can choose to
  supply a data file that will be embedded in the visualisation
  file. If no data file is given, the HTML visualisation will offer
  a file selection element, or the bare JSON output will refer to a
  file called 'data.csv'.
* Changes to Samplevis:
  * The Options box can now be opened/closed.
  * Added options to change the width of the bars and the space
    between subgraphs (markers).
  * Added options to filter by read count or percentage vs the
    highest allele of the marker.
  * Replaced deprecated 'zip' data transforms in the Vega spec with
    the new 'lookup' transform.
* Updated bundled Vega to v2.1.1.