Allow the update value for a StateVariable of type string to be
Allow the update value for a StateVariable of type string to be

 * a string
 * a comma-separated string
 * a list
 * a tuple.

Lists and tuples will be transformed into a comma-separated string.

ismaelgaudioso/Coherence,unintended/Cohen,opendreambox/python-coherence,furbrain/Coherence,ismaelgaudioso/Coherence,furbrain/Coherence,coherence-project/Coherence,sreichholf/python-coherence,coherence-project/Coherence,unintended/Cohen,opendreambox/python-coherence,sreichholf/python-coherence