Updated readme.md for 4.4.3 release.

Enable secure_element.h for doxygen

Fix AU915 and US915 TX_POWER values according to regional parameters …

…v1.0.3reva_0 specification.

Issue(Lora-net#572) Fix missing phy param implementation for PHY_MAX_…

…TX_POWER on RU region

Issue(Lora-net#596) Fix missing case for RU864_MAX_FCNT_GAP in RU864

Add NucleoL476RG platform support.

The SX126x development kit is based on a NucleoL476 board plus one of the mbed shields.

Corrected used ADC parameter.

Update the function LoRaMacCommandsRemoveStickyAnsCmds to remove all …

…occurrences of a sticky Mac command

Lora-net#529

Added Russia RU864 region support.

Lora-net#496

LoRaWAN v4.4.1 according to LoRaWAN Specification v1.0.2