enhancement - try to reconstruct the channel positions rather than return all nan


git-svn-id: svn+ssh://svn.fcdonders.nl/home/svnroot/fieldtrip/trunk@8565 0cf7c7f0-3615-4144-b4e6-68da3bce3cd0
automatically synchronized identical files to revision 8565

git-svn-id: svn+ssh://svn.fcdonders.nl/home/svnroot/fieldtrip/trunk@8566 0cf7c7f0-3615-4144-b4e6-68da3bce3cd0