Parse Accept-Ranges header in SETUP to use in ONVIF rtsp for absolute clock

[Ehsan Azarnasab]

Hi,

I added some patch to parse 'Accept-Ranges':'UTC' in the SETUP header in ONVIF cameras and use absolute "range: clock" which is required for *playback* from nvr:
https://bugzilla.gnome.org/show_bug.cgi?id=776601
https://bugzilla.gnome.org/show_bug.cgi?id=776929

This is my first patch to any Bugzilla! I appreciate if you could review 

Thanks
Ehsan