progress towards saving state

really I just want to commit to change branches.
saving to file works now

but I want to move all that code to voIOManager.
committing before I break anything.
getting close to being able to load

switching branches to fix some bugs
slightly different XML format for TreeHeatmap
can now load state (input files only)

also modified the open action to accept .xml state files.
enforce unique names for items in our data model
clear the data model before loading state from XML
Enable Visomics users to chain analyses together

This commit makes it possible to perform an analysis on the output of
another analysis.  To do this, I had to deal with the fact that most
of our analyses expect vtkExtendedTable as input, but produce
vtkTable as output.
fix failing test voDataBrowserWidgetTest
fix / improve PCA analysis

As of this commit, we can perform PCA on both our example data tables.
Make it so PLS can be run on the output of other analyses

This required me to beef up the code that converts analysis output
from vtkTable to vtkExtendedTable.
change Geiger's output to be "OutputType", not "ViewType"
new functionality to load & save analyses

So far I've only tested this on a simple example.
update to new version of Arbor icons
Merge branch 'SaveLoadState'

* SaveLoadState:
  update to new version of Arbor icons
  new functionality to load & save analyses
  change Geiger's output to be "OutputType", not "ViewType"
  Make it so PLS can be run on the output of other analyses
  fix / improve PCA analysis
  fix failing test voDataBrowserWidgetTest
  Enable Visomics users to chain analyses together
  clear the data model before loading state from XML
  enforce unique names for items in our data model
  can now load state (input files only)
  slightly different XML format for TreeHeatmap
  getting close to being able to load
  saving to file works now
  progress towards saving state