Add signal strength in home page

seems having some difference between RSSI of current signal and RSSI of
scanned AP - TBC

Author: Luc

esp8266/data/home.tpl

@@ -43,6 +43,7 @@ $INCLUDE[header.inc]$
 <label>Connection to: </label><label class="text-info">$STA_SSID$</label><BR>
 <label>Channel: </label><label class="text-info">$STA_CHANNEL$</label><BR>
 <label>Status: </label><label class="text-info">$STA_STATUS$</label><BR>
+<label>Signal strength: </label><label class="text-info">$STA_SIGNAL$%</label><BR>
 <label>DHCP Client: </label><label class="text-info">$STA_DHCP_STATUS$</label><BR>
 <label>IP: </label><label class="text-info">$STA_IP$</label><BR>
 <label>Gateway: </label><label class="text-info">$STA_GW$</label><BR>

esp8266/webinterface.cpp

@@ -205,6 +205,7 @@ const char VALUE_CHANGE_PASSWORD [] PROGMEM = "Change Password";
 const char MISSING_DATA [] PROGMEM = "Error: Missing data";
 const char EEPROM_NOWRITE [] PROGMEM = "Error: Cannot write to EEPROM";
 const char KEY_WEB_UPDATE [] PROGMEM = "$WEB_UPDATE_VISIBILITY$";
+const char KEY_STA_SIGNAL [] PROGMEM = "$STA_SIGNAL$";
 
 bool WEBINTERFACE_CLASS::isHostnameValid(const char * hostname)
 {
@@ -994,6 +995,9 @@ void handle_web_interface_root()
     } else {
         ValuesList.add(FPSTR(VALUE_DISCONNECTED));
     }
+    //Signal strength
+    KeysList.add(FPSTR(KEY_STA_SIGNAL));
+    ValuesList.add(intTostr(100+WiFi.RSSI()));
     //DHCP Client status
     GetDHCPStatus(KeysList, ValuesList);
     //IP address

keywords.txt

@@ -60,6 +60,7 @@ $STA_MAC$  : Mac address of Station
 $STA_SSID$ : SSID used by STA
 $STA_CHANNEL$ : Channel
 $STA_STATUS$ : Connection Status
+$STA_SIGNAL$ : Signal strength
 $STA_DHCP_STATUS$ : DHCP Client status
 $STA_IP$ : STA IP
 $STA_GW$ : STA Gateway