Fix conflict with master branch.

- Avoid single character String concatenations done via String literals instead of char literals, as this is inefficient because of temporary String creations (esp8266#6571).

Author: aerlon

libraries/ESP8266WiFiMesh/src/ESP8266WiFiMesh.cpp

@@ -372,7 +372,7 @@ transmission_status_t ESP8266WiFiMesh::exchangeInfo(WiFiClient &currClient)
 {
   verboseModePrint("Transmitting");  // Not storing strings in flash (via F()) to avoid performance impacts when using the string.
 
-  currClient.print(getMessage() + "\r");
+  currClient.print(getMessage() + '\r');
   yield();
 
   if (!waitForClientTransmission(currClient, _stationModeTimeoutMs))
@@ -585,11 +585,11 @@ void ESP8266WiFiMesh::attemptTransmission(const String &message, bool concluding
 
       if(_verboseMode) // Avoid string generation if not required
       {
-        verboseModePrint(String(F("AP acquired: ")) + currentSSID + String(F(", Ch:")) + String(currentWiFiChannel) + " ", false);
+        verboseModePrint(String(F("AP acquired: ")) + currentSSID + String(F(", Ch:")) + String(currentWiFiChannel) + ' ', false);
 
         if(currentNetwork.networkIndex != NETWORK_INFO_DEFAULT_INT)
         {
-          verboseModePrint("(" + String(WiFi.RSSI(currentNetwork.networkIndex)) + String(F("dBm) ")) + 
+          verboseModePrint('(' + String(WiFi.RSSI(currentNetwork.networkIndex)) + String(F("dBm) ")) + 
                            (WiFi.encryptionType(currentNetwork.networkIndex) == ENC_TYPE_NONE ? String(F("open")) : ""), false);
         }
 
@@ -665,7 +665,7 @@ void ESP8266WiFiMesh::acceptRequest()
       if (_client.connected())
       {
         verboseModePrint("Responding");  // Not storing strings in flash (via F()) to avoid performance impacts when using the string.
-        _client.print(response + "\r");
+        _client.print(response + '\r');
         _client.flush();
         yield();
       }

libraries/ESP8266WiFiMesh/src/EspnowMeshBackend.cpp

@@ -165,7 +165,7 @@ bool EspnowMeshBackend::activateEspnow()
       warningPrint("Failed to set ESP-NOW role! Maybe ESP-NOW peers are already added?");
 
     verboseModePrint("ESP-NOW activated.");
-    verboseModePrint("My ESP-NOW STA MAC: " + WiFi.macAddress() + "\n"); // Get the station MAC address. The softAP MAC is different.
+    verboseModePrint("My ESP-NOW STA MAC: " + WiFi.macAddress() + '\n'); // Get the station MAC address. The softAP MAC is different.
 
     return true;
   } 

libraries/ESP8266WiFiMesh/src/MeshBackendBase.cpp

@@ -282,11 +282,11 @@ void MeshBackendBase::printAPInfo(const NetworkInfoBase &apNetworkInfo)
     mainNetworkIdentifier = macToString(apNetworkInfo.BSSID());
   }
 
-  verboseModePrint(String(F("AP acquired: ")) + mainNetworkIdentifier + String(F(", Ch:")) + String(apNetworkInfo.wifiChannel()) + " ", false);
+  verboseModePrint(String(F("AP acquired: ")) + mainNetworkIdentifier + String(F(", Ch:")) + String(apNetworkInfo.wifiChannel()) + ' ', false);
 
   if(apNetworkInfo.RSSI() != NetworkInfoBase::defaultRSSI)
   {
-    verboseModePrint("(" + String(apNetworkInfo.RSSI()) + String(F("dBm) ")) + 
+    verboseModePrint('(' + String(apNetworkInfo.RSSI()) + String(F("dBm) ")) + 
                      (apNetworkInfo.encryptionType() == ENC_TYPE_NONE ? String(F("open")) : ""), false);
   }
 

libraries/ESP8266WiFiMesh/src/TcpIpMeshBackend.cpp

@@ -247,7 +247,7 @@ transmission_status_t TcpIpMeshBackend::exchangeInfo(WiFiClient &currClient)
 {
   verboseModePrint("Transmitting");  // Not storing strings in flash (via F()) to avoid performance impacts when using the string.
 
-  currClient.print(getCurrentMessage() + "\r");
+  currClient.print(getCurrentMessage() + '\r');
   yield();
 
   if (!waitForClientTransmission(currClient, _stationModeTimeoutMs))
@@ -550,7 +550,7 @@ void TcpIpMeshBackend::acceptRequests()
     if (_client.connected())
     {
       verboseModePrint("Responding");  // Not storing strings in flash (via F()) to avoid performance impacts when using the string.
-      _client.print(response + "\r");
+      _client.print(response + '\r');
       _client.flush();
       yield();
     }