Use definitions from table 100 of EN 300 468.

Setting of teletext_type and teletext_magazine was 1 bit off, instead
of bits 5/3, bits 6/2 were used.

Add missing desc5f_set_specifier() function and also print the specifier
as hex.

Add missing init and set functions and also fix printing.

Add desc48_set_length() function.

Add missing init and set functions.

Add missing init and set functions and also fix return type of
desc43_get_modulation() function.

Add missing init and set functions. Also print service_type as
hex number.

Due to missing casts the function is not returning correctly the top
8 bits (32-40) of UTC_time field.

Without these messages the user have no idea what is happening and
this can be very confusing.