Sorry for this :( But this makes it more in sync with expected type
naming in gobject (i.e. CamelCase and not CamelMAYBECase).
Also split descriptor type enums into the different variants:
* ISO H.222.0 / 13818-1 (i.e. standard mpeg-ts)
* DVB
* ATSC
* ISDB
* miscellaneous
This will avoid future clashes when specs use the same descriptor type
c1366efcd6