WIP commit. Fixes for availableSeekRange response header

Fixed the header name. Was going in as TimeSeekRange due to cut/paste.

Fixed the ODIDDataSource.from_live constructor to set resource_uri memvar.

Made the reading of the limited_operation_mode resource parameter more
 robust.

Improved offsets_for_time_range() to deal with single-point non-inclusive
 ranges (e.g. "0-0")

Cleaned up more logging.

Tested TimeSeekRange and availableSeekRange processing with live (unstarted)
 resources and non-live resources.
WIP commit. Implemented on-demand sim start, reading/setting of live-start-offset, index processing cleanup

Added the live_sim_table HashTable to the ODIDMediaEngine. It now keeps the
 list of live simulators by resource name (short path).

The ME autostart_live_sims memvar is now set when "live-sim-start" is set to
 "on-demand" in the rygel.conf.

ODIDMediaEngine.create_data_source_for_resource() now starts the live sim
 when autostart_live_sims is set. The setting of the autostop parameter is
 precipitated a refactoring of the index code so the content duration can
 be easily retrieved.

Added ODIDIndexEntry class to contain logic/knowledge of ODID index file
 entries. Changed the MediaEngine/DataSource/Util code to use the new
 class. The logic was getting just a little to spread out/messy.

Ran non-live TimeSeekRange/Range tests (since some of the index logic was
 refactored)

Ran live tests. Saw first signs of properly-formed availableSeekRange
 response headers.