Fix TS480 ptt off -- seems some versions of it don't return anything at all

for RX; command where some do when in PTT.  So we won't expect any return at all like all other Kenwood rigs.
Start migrating main version number to use YYYYMMDD.  Backends which use generic brand commands will still use numeric versions.  So the TS480 right now will become 20200329.6

rigs/kenwood/kenwood.c

@@ -3198,24 +3198,6 @@ int kenwood_set_ptt(RIG *rig, vfo_t vfo, ptt_t ptt)
     default: return -RIG_EINVAL;
     }
 
-    if (ptt == RIG_PTT_OFF && RIG_MODEL_TS480 == rig->caps->rig_model)
-    {
-        /* if not in PTT TS-480 will return RX0; */
-        ptt_t ptttmp;
-        int err = kenwood_get_ptt(rig, vfo, &ptttmp);
-
-        if (err != RIG_OK)
-        {
-            return err;
-        }
-
-        if (ptttmp)
-        {
-            char ackbuf[8];
-            return kenwood_transaction(rig, ptt_cmd, ackbuf, sizeof(ackbuf));
-        }
-    }
-
     return kenwood_transaction(rig, ptt_cmd, NULL, 0);
 }
 

rigs/kenwood/kenwood.h

@@ -27,7 +27,7 @@
 #include <string.h>
 #include "token.h"
 
-#define BACKEND_VER "1.8"
+#define BACKEND_VER "20200329"
 
 #define EOM_KEN ';'
 #define EOM_TH '\r'

rigs/kenwood/ts480.c

@@ -481,7 +481,7 @@ const struct rig_caps ts480_caps =
     .mfg_name = "Kenwood",
     .version = BACKEND_VER ".6",
     .copyright = "LGPL",
-    .status = RIG_STATUS_UNTESTED,
+    .status = RIG_STATUS_STABLE,
     .rig_type = RIG_TYPE_TRANSCEIVER,
     .ptt_type = RIG_PTT_RIG_MICDATA,
     .dcd_type = RIG_DCD_RIG,