Better MPEG decoding support for DAB channels

• replace pl_mpeg with mpg123 for greater MPEG support (MPEG 1.0, 2.0, 2.5 and layer I, II, III) (#13)
• use and display ensemble and service unique identifiers correctly (#8)
• support wav files and various raw file formats in basic_radio_app (#11)
• various small fixes (#9, #10)
• hide wierd dummy/placeholder services which dont have any audio or data service components (7397751)