Add marking actions to CIF to mCRL2 output

CIF specifications can include marker predicates. Marking is currently ignored when transforming a CIF specification to mCRL2. It can be useful to be able to specify properties relating to the marking, in mCRL2. For this to be possible, the mCRL2 specification would need to include information about the marking of the CIF model. Similar to how we add value actions, we could allow to (optionally) add marking options. If the state is marked, the marking action would be enabled.