BUG: #2326 mark a node as modified if the name has changed

When the user has changed the name of a node this is
reflected in the suggested name of the file (see issue #3125).
With this fix the node is also marked as modified so that
it will be checked for saving.

This means that changing the name of a node in the scene will
cause it to be saved to a new file on disk which is a slight change
in behavior and may cause people to use more disk space.  But in
general I think this is safer and more clear, since file names will
always match the name of the node in the scene and users will
prefer that I believe.

git-svn-id: http://svn.slicer.org/Slicer4/trunk@22260 3bd1e089-480b-0410-8dfb-8563597acbee
BUG: Name SampleData internal widget for easy referencing by QtTesting

See #2808

git-svn-id: http://svn.slicer.org/Slicer4/trunk@22261 3bd1e089-480b-0410-8dfb-8563597acbee
COMP: Always build qSlicerPersistentCookieJar

It is being used by qSlicerWebWidget which is not conditionally built by
Slicer_BUILD_EXTENSIONMANAGER_SUPPORT

git-svn-id: http://svn.slicer.org/Slicer4/trunk@22262 3bd1e089-480b-0410-8dfb-8563597acbee
ENH: 2487. Added new method: void vtkMRMLHierarchyNode::MoveInParent(int increment)
Added tests for this method in vtkMRMLHierarchyNodeTest3.

git-svn-id: http://svn.slicer.org/Slicer4/trunk@22263 3bd1e089-480b-0410-8dfb-8563597acbee