Added destructors

src/TinyGsmClientA6.h

@@ -184,6 +184,7 @@ public:
   {
     memset(sockets, 0, sizeof(sockets));
   }
+  virtual ~TinyGsmA6() {}
 
   /*
    * Basic functions

src/TinyGsmClientBG96.h

@@ -220,6 +220,7 @@ public:
   {
     memset(sockets, 0, sizeof(sockets));
   }
+  virtual ~TinyGsmBG96() {}
 
   /*
    * Basic functions

src/TinyGsmClientESP8266.h

@@ -205,6 +205,7 @@ public:
   {
     memset(sockets, 0, sizeof(sockets));
   }
+  virtual ~TinyGsmESP8266() {}
 
   /*
    * Basic functions

src/TinyGsmClientM590.h

@@ -181,6 +181,7 @@ public:
   {
     memset(sockets, 0, sizeof(sockets));
   }
+  virtual ~TinyGsmM590() {}
 
   /*
    * Basic functions

src/TinyGsmClientM95.h

@@ -220,6 +220,7 @@ public:
   {
     memset(sockets, 0, sizeof(sockets));
   }
+  virtual ~TinyGsmM95() {}
 
   /*
    * Basic functions

src/TinyGsmClientMC60.h

@@ -224,6 +224,7 @@ public:
   {
     memset(sockets, 0, sizeof(sockets));
   }
+  virtual ~TinyGsmMC60() {}
 
   /*
    * Basic functions

src/TinyGsmClientSIM7000.h

@@ -249,6 +249,7 @@ public:
   {
     memset(sockets, 0, sizeof(sockets));
   }
+  virtual ~TinyGsmSim7000() {}
 
   /*
    * Basic functions

src/TinyGsmClientSIM800.h

@@ -244,6 +244,7 @@ public:
   {
     memset(sockets, 0, sizeof(sockets));
   }
+  virtual ~TinyGsmSim800() {}
 
   /*
    * Basic functions

src/TinyGsmClientUBLOX.h

@@ -254,6 +254,7 @@ public:
     memset(sockets, 0, sizeof(sockets));
     isCatM = false;  // For SARA R4 and N4 series
   }
+  virtual ~TinyGsmUBLOX() {}
 
   /*
    * Basic functions

src/TinyGsmClientXBee.h

@@ -277,6 +277,8 @@ public:
       inCommandMode = false;
       memset(sockets, 0, sizeof(sockets));
   }
+  
+  virtual ~TinyGsmXBee() {}
 
   /*
    * Basic functions

src/TinyGsmCommon.h

@@ -211,6 +211,7 @@ public:
   TinyGsmModem(Stream& stream)
     : stream(stream)
   {}
+  virtual ~TinyGsmModem() {}
 
   /*
    * Basic functions
@@ -331,6 +332,4 @@ public:
 };
 
 
-
-
 #endif