1. Update boot.bin to v1.5;
2. Add wifi_station_set/get_hostname API;
3. Update SmartConfig to version 2.5.3;
4. Support GPIO wakeup;
5. Enable IGMP in LWIP;
6. Add espconn_init in espconn.h;
7. Update esp_init_data_default.bin;
8. IROM start address changed to 0x20000.