Fixed the problem with default settings of the chart (#415).
Added persistence of the automatic history refresh and future buffer.
Eliminated a warning in the EditItemsCommand.
Changed the names of exported column in the SelectionValueExporter.
Bugfix: if futureBuffer was set, the timerange change was ignored.
Merge pull request #418 from jbobnar/master

Legend problem (fixes #415) and a few other minor issues