tests: dashdemux: add unit tests for checking the parsing of MPD element
Create a dash test target and add unit tests that check the parsing of
attributes of the MPD element and the following child elements:
- baseURL
- program information
- location
- metrics
These tests check the compliance of parts of the MPD parser in the
dashdemux element against the DASH specification [1].
[1] http://standards.iso.org/ittf/PubliclyAvailableStandards/c065274_ISO_IEC_23009-1_2014_Electronic_inserts.zip
http://standards.iso.org/ittf/PubliclyAvailableStandards/c065274_ISO_IEC_23009-1_2014.zip
https://bugzilla.gnome.org/show_bug.cgi?id=750390