dr_a1.h: update and correct documentation
dr_a1.h: update and correct documentation

mwgoldsmith/dvbpsi,mkrufky/libdvbpsi,paraeco/libdvbpsi,mwgoldsmith/dvbpsi,vlc-mirror/libdvbpsi,mkrufky/libdvbpsi,paraeco/libdvbpsi,mkrufky/libdvbpsi,vlc-mirror/libdvbpsi,vlc-mirror/libdvbpsi,mwgoldsmith/dvbpsi,mwgoldsmith/dvbpsi,paraeco/libdvbpsi,paraeco/libdvbpsi