BUG: confirm delete of markups

Add a message box to tell the user how many markups they
are about to delete and let them cancel. Option to
not show the message again.

COMP: cleaned up unused variable warnings

Fixes issue #3324



git-svn-id: http://svn.slicer.org/Slicer4/trunk@22332 3bd1e089-480b-0410-8dfb-8563597acbee
BUG: remove fiducial settings from the tutorial self test GUI

Remove left over code from copying the add many fiducials self test.
Replaced them with screen shot parameters to help with making the tutorial,
a check box to turn them on (off by default) and a slider to set the scale
(1 by default).
Tweaked the test: make sure that the fiducial list is named the same
as when a user would create one. Make the slices visible in 3D.

Issue #3328



git-svn-id: http://svn.slicer.org/Slicer4/trunk@22333 3bd1e089-480b-0410-8dfb-8563597acbee