[vdr] incompatibiliy between radio plugin and all mp3 plugins

in cPluginRadio::Replaying(), radio.c expects the replayed recording to be a VDR record. But mp3plugins like mp3, music, muggle use this mechanism for simple audio files.

So if both plugins are loaded, radio will emit messages like vdr: [16883] ERROR: /Musik/shout/Bach/Johann Sebastian Bach - Adagio ma non tanto.mp3/001.vdr: Ist kein Verzeichnis

Now my question is: Is this mechanism is thought to be used only for VDR recordings ore more generally - the latter I hope.

A simple solution would be if the radio plugin could check if the recording is actually a VDR recording. Right now it just calls

cFileName fn(FileName, false, true);

maybe a VDR core helper function like isVDRRecording would be helpful for this.