Remove is connected method.

Author: ghent360

Diff for: cores/arduino/USBSerial.cpp

@@ -187,11 +187,6 @@ bool USBSerial::rts(void)
   return false;
 }
 
-bool USBSerial::isConnected()
-{
-  return CDC_connected();
-}
-
 USBSerial::operator bool()
 {
   bool result = false;

Diff for: cores/arduino/USBSerial.h

@@ -53,7 +53,6 @@ class USBSerial : public Stream {
     uint8_t numbits();
     bool dtr();
     bool rts();
-    bool isConnected();
     enum {
       ONE_STOP_BIT = 0,
       ONE_AND_HALF_STOP_BIT = 1,