fix header display of associated table
make sure RExternalPackages "builds" after VisomicsData

This commit ensures that we've already downloaded VisomicsData
before we try to install geiger.
bump build number for next round of feedback
combine a tree & a table after they've been loaded

A new action under the File menu allows you to associate a table
with a tree after they've both been loaded.  This commit also fixes
vtkExtendedTable so that it can handle string data as well as numerical
data.
Merge branch 'FixGeigerBugs'

* FixGeigerBugs:
  combine a tree & a table after they've been loaded
  bump build number for next round of feedback
  make sure RExternalPackages "builds" after VisomicsData
  fix header display of associated table