WIP refactoring ODIDDataSource.preroll() into preroll_static_resource() and preroll_live_resource()

While adding support for S0==0 support, the code got out of control.
 Started splitting up the logic.

The live sim now has an extractable State and Mode. These will be
 used in switch statements to better organize the processing logic.

ODIDMediaEngine.create_resource is now using State/Mode. The method
 is pretty long though, so could probably use some refactoring as
 well. But already caught a bug where the logic wasn't properly
 representing stopped sims in pure-live mode (S0=Sn).

Started using the Vala "in" operator for bitfield tests.

Tested for regressions with static content. All seems well. The
 table is set for a new-and-improved live preroll
 (preroll_live_resource())...