restructuring - only call undobalancing if current is different from none


git-svn-id: svn+ssh://svn.fcdonders.nl/home/svnroot/fieldtrip/trunk@8571 0cf7c7f0-3615-4144-b4e6-68da3bce3cd0
automatically synchronized identical files to revision 8571

git-svn-id: svn+ssh://svn.fcdonders.nl/home/svnroot/fieldtrip/trunk@8572 0cf7c7f0-3615-4144-b4e6-68da3bce3cd0