add QtTesting to Visomics

Add the QtTesting project to Visomics' SuperBuild.
This allows us to record and playback GUI interactions as tests.
A handful of such tests are included in this commit.

Other changes:

* reintroduce "load sample table" button.  We now have two
  load sample buttons: one for the liver table, and one for the
  anolis tree + heatmap.

* Cache analysis server password.  This makes it so we don't
  have to hardcode this password in each analysis .XML file.
Merge branch 'qt_testing'

* qt_testing:
  add QtTesting to Visomics