Removing mesh dimension restriction from PenetrationLocator (closes #3099)

When having a higher dimensional mesh and using lower-dimensional
elements, PenetrationLocator cannot deal with it, since it assumes that
all elements have dimension equal to the mesh dimension.
Merge pull request #3100 from andrsd/3099

Removing mesh dimension restriction from PenetrationLocator (closes #309...
Merge commit '6d46449850827aea56493a71d196676964a3f45a'