Revert "Added function on WString class to export char ptr"

This reverts commit a0c96bebdd.

hardware/arduino/cores/arduino/Print.cpp

@@ -53,8 +53,11 @@ size_t Print::print(const __FlashStringHelper *ifsh)
 
 size_t Print::print(const String &s)
 {
-  write((const uint8_t*)s.c_str(), s.length());
-  return s.length();
+  size_t n = 0;
+  for (uint16_t i = 0; i < s.length(); i++) {
+    n += write(s[i]);
+  }
+  return n;
 }
 
 size_t Print::print(const char str[])

hardware/arduino/cores/arduino/WString.cpp

@@ -642,8 +642,4 @@ long String::toInt(void) const
 	return 0;
 }
 
-char* String::c_str() const
-{
-	return buffer;
-}
 

hardware/arduino/cores/arduino/WString.h

@@ -169,7 +169,6 @@ public:
 
 	// parsing/conversion
 	long toInt(void) const;
-	char* c_str() const;
 
 protected:
 	char *buffer;	        // the actual char array