Added Range.dtcp.com support for live modes & a couple fixes

ODIDDataSource.preroll_livesim_resource() changes:

 Added processing of DTCPCleartextRequest.

 Added generation of DTCPCleartextResponse.

 Simplified the no-seek logic. It really only needed one state check.

 Renamed send_indefinitely to send_unbound

Fixed ODIDUtil.offsets_within_time_range () to use a <=/>= test
 when comparing the range start. This allows for proper behavior
 when a range returned from offsets_within_time_range () back
 into the function (as happens when processing a time seek). This
 resolved an issue where the TimeSeekRange response on stopped sim
 would not start with npt=0.