I2C EEPROM support for OTA using dual Optiboot #802 (#834)

* Added support for I2C EEPROM OTA

* EEPROM OTA now uses extEEPROM as driver

* Compiler warning fix

* Style check fixes

* Fix doxygen warnings of I2CEeprom

* Use bool instead of boolean in I2CEeprom shim

* Fix re-merged style problem

MySensors.h

@@ -172,7 +172,11 @@ MY_DEFAULT_RX_LED_PIN in your sketch instead to enable LEDs
 
 // FLASH
 #if defined(MY_OTA_FIRMWARE_FEATURE)
+#if defined(MY_OTA_USE_I2C_EEPROM)
+#include "drivers/I2CEeprom/I2CEeprom.cpp"
+#else
 #include "drivers/SPIFlash/SPIFlash.cpp"
+#endif
 #include "core/MyOTAFirmwareUpdate.cpp"
 #endif