Make it illegal to call dimension() on an array node.
Make it illegal to call dimension() on an array node.

Also implement properly dimension() for random access nodes.

babrodtk/equelle,babrodtk/equelle,babrodtk/equelle,atgeirr/equelle,atgeirr/equelle,atgeirr/equelle,sintefmath/equelle,sintefmath/equelle,sintefmath/equelle,sintefmath/equelle,atgeirr/equelle,babrodtk/equelle,babrodtk/equelle,babrodtk/equelle,sintefmath/equelle,atgeirr/equelle,sintefmath/equelle,atgeirr/equelle,atgeirr/equelle,sintefmath/equelle,sintefmath/equelle,atgeirr/equelle,babrodtk/equelle