Change Dry and Heat fan speeds.

* According to @soumaxetuirk : "In Dry mode FAN is restricted to "auto" 
instead of low. And heat mode FAN is restricted high only."
For: 
#1056 (comment)

src/ir_Hitachi.cpp

@@ -480,15 +480,16 @@ void IRHitachiAc1::setMode(const uint8_t mode) {
   switch (mode) {
     case kHitachiAc1Auto:
       setTemp(kHitachiAc1TempAuto);
-      setFan(kHitachiAc1FanAuto, true);
       // FALL THRU
+    case kHitachiAc1Dry:
     case kHitachiAc1Fan:
     case kHitachiAc1Heat:
     case kHitachiAc1Cool:
-    case kHitachiAc1Dry:
       setBits(&remote_state[kHitachiAc1ModeByte], kHitachiAc1ModeOffset,
               kHitachiAc1ModeSize, mode);
-      setSleep(getSleep());  // Correct the sleep mode if required.
+      // Correct the sleep mode & fan speeds if required.
+      setSleep(getSleep());
+      setFan(getFan());
       break;
     default: setMode(kHitachiAc1Auto);
   }
@@ -524,14 +525,18 @@ uint8_t IRHitachiAc1::getFan(void) {
 void IRHitachiAc1::setFan(const uint8_t speed, const bool force) {
   if (!force) {
     switch (getMode()) {
-      case kHitachiAc1Auto:
-      case kHitachiAc1Dry: return;  // Speed change not allowed in these modes.
+      case kHitachiAc1Auto:  // These modes are resticted to Auto speed.
+      case kHitachiAc1Dry:
+        setFan(kHitachiAc1FanAuto, true);
+        return;
+      case kHitachiAc1Heat:  // These modes are resticted to High speed.
+        setFan(kHitachiAc1FanHigh, true);
+        return;
     }
   }
   switch (speed) {
     case kHitachiAc1FanAuto:
       switch (getMode()) {
-        case kHitachiAc1Heat:
         case kHitachiAc1Fan: return;  // Auto speed not allowed in these modes.
       }
       // FALL THRU