enhancement: standard mri contains unit and coordsys fields

git-svn-id: svn+ssh://svn.fcdonders.nl/home/svnroot/fieldtrip/trunk@9048 0cf7c7f0-3615-4144-b4e6-68da3bce3cd0
bugfix #2424 - handling of elec/grad for creating a layout improved

git-svn-id: svn+ssh://svn.fcdonders.nl/home/svnroot/fieldtrip/trunk@9049 0cf7c7f0-3615-4144-b4e6-68da3bce3cd0