BUG: CLI several module GUI bugs

Fix for need to re-select node after changing some parameters (http://www.na-mic.org/Bug/view.php?id=4090):

• Create a CLI node when switching to CLI if a compatible node is not available already (to not require users create a CLI node before starting interacting with the module). (http://www.na-mic.org/Bug/view.php?id=4090)
• Disable CLI module parameter editing widgets if no CLI node is selected (e.g., after scene close).
• Prevent crash in qSlicerCLIModuleUIHelper::setCommandLineModuleParameter when the method is called before a scene is set.

Fix for editable output values (http://www.na-mic.org/Bug/view.php?id=2402 and http://www.na-mic.org/Bug/view.php?id=2842):

• Prevent editing of CLI output values.
• Print current parameter values in vtkMRMLCommandLineModuleNode::PrintSelf instead of the module description, which is long and in general not informative.
• Added a method for printing module description (vtkMRMLCommandLineModuleNode::GetModuleDescriptionAsString).

Fix for editing vector fields:

• Prevent moving the cursor to the end of the line when editing a vector field (e.g., try to edit the first value in Float Vector Parameter in Execution Model Tour)

git-svn-id: http://svn.slicer.org/Slicer4/trunk@24811 3bd1e089-480b-0410-8dfb-8563597acbee