Bug 499003 - Fix visibleWhen of contribution to compareWithMenu

Fix the visibleWhen expression for the
org.eclipse.emf.compare.ide.ui.emfComparisonSourceCompareCommand so that
the command is hidden if the current selection is empty. 

Fix spelling of the command's label.

Remove duplicate definition of the compareWithMenu.

Change-Id: I0c1c9b22fcf41a65a7770c12521e2a930a26eccc
Signed-off-by: Andreas Mayer <anma-e@gmx.de>
2 files changed