1. added AT+ command "AT+MSGHEX" and change previous RHF76_ATCMD_FMT_SEND_MSGHEX to RHF76_ATCMD_FMT_SEND_CMSGHEX
2. implement send_unconfirmed with a non-breaking approach: added int (*send_unconfirmed)(const void *buf, size_t len); event handle in lora_module_st; added int tos_lora_module_send_unconfirmed(const void *buf, size_t len); in lora_module_wrapper.c; and implement static int rhf76_send_unconfirmed(const void *buf, size_t len) in RHF76.c
3. added { "+MSGHEX: PORT:", rhf76_incoming_data_process } in event array rhf76_at_event so that the device is able to process the downlink data when it is configurated to send unconfirmed message.
4. added AT+ command "AT+REPT", and implement the static int rhf76_set_repeat(uint8_t num) to enable user to set repeat times (1-15) while using "unconfirmed message"
5. updated the instructions of implemeting up-link parser and downlink parser on the server in the file "..\board\NUCLEO_STM32L073RZ\BSP\Src\lora_demo.c"
1. modified the HTS221: removed magic numbers, added a sensor_tempnhumi_t struct to accommodate temperature and humidity data
2. added .h and .c files for LIS3MDL magnetic sensor
3. added .h and .c files for LPS22HB pressure sensor
3. added IAR (EWARM) project for lorawan example
4. added bsp.c and bsp.h to manager the sensors
