Partially complete rework of all the decoders to avoid seeking inside the

fluxmap. This requires resetting the FluxDecoder, which loses any pending
state, resulting in bad reads for (some) formats which don't have gaps between
sectors --- the DVK MX is the main victim.

arch/aeslanier/decoder.cc

@@ -30,17 +30,14 @@ public:
 		AbstractDecoder(config)
 	{}
 
-    RecordType advanceToNextRecord()
+    nanoseconds_t advanceToNextRecord() override
 	{
-		_sector->clock = _fmr->seekToPattern(SECTOR_PATTERN);
-		if (_fmr->eof() || !_sector->clock)
-			return UNKNOWN_RECORD;
-		return SECTOR_RECORD;
+		return seekToPattern(SECTOR_PATTERN);
 	}
 
     void decodeSectorRecord()
 	{
-		/* Skip ID mark. */
+		/* Skip ID mark (we know it's a AESLANIER_RECORD_SEPARATOR). */
 
 		readRawBits(16);