Allow accessing constant, read-only variables that have been initialized explicitly (static arrays or aranges) in standalone scripts. This should allow the double indexing from the previous commit to work in standalone scripts as well.
Fix a bug that had been silently introduced in commit c6851d75: `CodeRunner` objects were not automatically added to magic networks.
Raise a NotImplementedError when linking to synaptic variables
Refactor the `Variables.add_reference` call to not expect a `Variable` object but a `Group` and a name
Fix the indexing for subexpressions that refer to linked variables.