Merge pull request pycom#277 from pycom/stable_r2_update

Merge pull request pycom#276 from pycom/rc8_update

[v1.20.0.rc7.2]

- Merge IDF release 3.1 updates
- Fix Wifi connection resuming after more than 1  machine sleep cycle

[Bug Fix]: v1.18.2.r1

Fix for wrong Kw arguments acquisition in LTE.attach and LTE()

v1.20.0.rc7.1

- MicroPython API to Enable/Disable Bluetooth Modem sleep
- Updated Pybytes Frozen Scripts

Firmware Release Candidate v1.20.0.rc7 - Pybytes v0.9.7

## New Features
* Pymesh feature added from Pygo

## Improvments
* Adding do_handshake for non-blocking sockets
* Gracefully handle EAGAIN return of Socket.write in AwsMQTT lib
* make openthread over lora a build-time configuration option (Author: @martijnthe)
* Added factory LTE modem reset option and  method to check UE coverage
* Updated Pybytes lib

## Bug Fixes
* Fix an issue in cleaning up user threads during of soft-reset
* Fix issue causing Device crash when safe booting (CTRL-F) while BLE/Wlan enabled
* LTE module bug fixes
* Fix Makefile bug where SIPY FIPY and LOPY4 excluded secure boot

co-authored by: @Xykon [cehlers@pycom.io](mailto:cehlers@pycom.io) and @martijnthe

Merging Fixes and updates from dev/master pycom#262

* esp32/modlte: Added factory modem reset option , method to check UE coverage and Bug fixes (pycom#17)

* Esp32/frozen/MQTTlib: Gracefully handle EAGAIN return of Socket.write

* esp32/mpthreadport.c: fix an issue in cleaning up user threads during of soft-reset (pycom#14)

Fixes issue [PYFW-197]
# Conflicts:
#	esp32/mpthreadport.c

* esp32/mphal: Fix issue causing Device crash when safe booting (CTRL-F) while BLE/Wlan enabled (pycom#15)

# Conflicts:
#	esp32/mods/modwlan.c

* esp32/modlte: minor fix

* esp32/make: Fix makefile bug excluding SIPY FIPY LOPY4 from secure Boot process

esp32/bootloader: increased Delay for RGB LED init to 300us

Update README.md

Firmware version [v1.18.1.r6]

-Fixed issue of LTE connection termination when `lte.isattached()` is called after PPP interface established