An improved patch for the Client part of issue 416 (adding a multi-byte read). This one moves all of the checking into recv, so that single-byte reads also benefit. It also returns -1 if there's no data available unless we've reached EOF, in which case it returns 0.

libraries/Ethernet/Client.h

@@ -17,6 +17,7 @@ public:
   virtual void write(const uint8_t *buf, size_t size);
   virtual int available();
   virtual int read();
+  virtual int read(uint8_t *buf, size_t size);
   virtual int peek();
   virtual void flush();
   void stop();