added Z to datatime.time serializer to encode UTC timezone
reworked LossyTransforSerializer into a plain SetSerializer
added tests for serializer, statical definition of serializer lookup dictionary, and indiviual serializers for datetime, date, and time objects
fixed serializer lookup dictionary identation and using type name strings directly
refined testing of sets in serialiser
Merge pull request #15 from adrpar/serializer_utc_compliancy

Serialiser improvements and tests