Added missing virtual destructors

Author: andreagilardoni

api/Client.h

@@ -27,6 +27,7 @@ namespace arduino {
 class Client : public Stream {
 
 public:
+  virtual ~Client() {};
   virtual int connect(IPAddress ip, uint16_t port) =0;
   virtual int connect(const char *host, uint16_t port) =0;
   virtual size_t write(uint8_t) =0;

api/HardwareI2C.h

@@ -26,6 +26,7 @@ namespace arduino {
 class HardwareI2C : public Stream
 {
   public:
+    virtual ~HardwareI2C() {}
     virtual void begin() = 0;
     virtual void begin(uint8_t address) = 0;
     virtual void end() = 0;

api/HardwareSerial.h

@@ -87,6 +87,7 @@ namespace arduino {
 class HardwareSerial : public Stream
 {
   public:
+    virtual ~HardwareSerial() {}
     virtual void begin(unsigned long) = 0;
     virtual void begin(unsigned long baudrate, uint16_t config) = 0;
     virtual void end() = 0;

api/Printable.h

@@ -33,6 +33,7 @@ class Print;
 class Printable
 {
   public:
+    virtual ~Printable() {}
     virtual size_t printTo(Print& p) const = 0;
 };
 

api/Server.h

@@ -25,6 +25,7 @@ namespace arduino {
 
 class Server : public Print {
   public:
+    virtual ~Server() {}
     virtual void begin() = 0;
 };
 

api/Stream.h

@@ -62,6 +62,7 @@ class Stream : public Print
     virtual int peek() = 0;
 
     Stream() {_timeout=1000;}
+    virtual ~Stream() {}
 
 // parsing methods
 

api/String.h

@@ -81,7 +81,7 @@ class String
 	explicit String(unsigned long, unsigned char base=10);
 	explicit String(float, unsigned char decimalPlaces=2);
 	explicit String(double, unsigned char decimalPlaces=2);
-	~String(void);
+	virtual ~String(void);
 
 	// memory management
 	// return true on success, false on failure (in which case, the string

api/Udp.h

@@ -42,6 +42,8 @@ namespace arduino {
 class UDP : public Stream {
 
 public:
+  virtual ~UDP() {}
+
   virtual uint8_t begin(uint16_t) =0;  // initialize, start listening on specified port. Returns 1 if successful, 0 if there are no sockets available to use
   virtual uint8_t beginMulticast(IPAddress, uint16_t) { return 0; }  // initialize, start listening on specified multicast IP address and port. Returns 1 if successful, 0 on failure
   virtual void stop() =0;  // Finish with the UDP socket