I2C clock streching on esp8266.

using printf - remove \ infront of #define - line was not displayed correct without

// insert after last [#include](https://forum.espruino.com/se­arch/?q=%23include)
extern int os_printf_plus(const char *format, ...)  __attribute__((format(printf, 1, 2)));
\#define printf os_printf_plus

.......

error:
  i2c_master_stop();
  //jsError("> I2C streching too long\n");
  printf("> I2C streching too long\n");
  return -1; 
}

compile output:

targets/esp8266/i2c_master.c: In function 'i2c_master_readByte':
targets/esp8266/i2c_master.c:330:9: error: implicit declaration of function 'i2c_master_getDD' [-Werror=implicit-function-declaration]
         while ( i2c_master_getDD()==0 && count--) { // PB 36000/1000*4=144
         ^
targets/esp8266/i2c_master.c: At top level: