Fine-grained tweaking of Series-related type/properties links.
Emphasis on domainIncludes rather than rangeIncludes, we
push media-related properties down onto TVSeries, RadioSeries,
VideoGameSeries and MovieSeries. For example, all of these
might have actor, whereas a MovieSeries doesn't usually have
episodes. Also further legacy cleanup removing redundant types.

The Series type has a new more general description.

We move Periodical under Series, and add MovieSeries and BookSeries
as placeholders.

Issue tracking:

https://github.com/rvguha/schemaorg/issues/148
https://github.com/rvguha/schemaorg/issues/169