* Small grammar fixes and clarifications

Just fixed some small grammar issues in the comments and clarified a few things that might seem confusing.

* More spelling fixes that I introduced...

This fixes the compile error when we include SPI.h

* Update mDNS and LEDC

* update toolchain

* Update IDF to 1c3dd23

* Advertise the board variant for Arduino OTA

* Add generic variant definition for mDNS

Update to make use of SSL a bit less confusing by ensuring errors are generated if the wrong method is called to retrieve the data stream. (#934)

* Allow configuration of Ethernet PHY clock source
Refer to https://github.com/espressif/esp-idf/pull/1127
The internal APLL can be used to generate the 50MHz clock for the internal EMAC and the external Ethernet PHY.
The clock can either be input on GPIO0 (as before) or output on GPIO0, GPIO16 or GPIO17 (only GPIO17 extensively tested).
New example available.

* Allow configuration of Ethernet PHY clock source
Refer to https://github.com/espressif/esp-idf/pull/1127
The internal APLL can be used to generate the 50MHz clock for the internal EMAC and the external Ethernet PHY.
The clock can either be input on GPIO0 (as before) or output on GPIO0, GPIO16 or GPIO17 (only GPIO17 extensively tested).
New example available.

Make sure to remove that next rebuild

Closes: https://github.com/espressif/arduino-esp32/pull/820

When user selected HSPI with SPIClass name(HSPI) ESP was, by default,
still using VSPI ports (the ones defined in pins_arduino.h).
With this change when user selects HSPI then HSPI default ports will be
used.
If user won't specify HSPI then VSPI default ports will be used.
If user will specify SCLK, MOSI, MISO and SS with SPI.begin() then user
defined ports will be used no matter if VSPI or HSPI is selected.
With this change fe. SD library can use default HSPI ports. It was
possible to
pass HSPI SPI instance to SD lib, however even then it was using VSPI
ports which were (probably) GPIO matrixed to HSPI.

* Don't escape folders which are already arguments

* Drop "stage" suffix from @platformio dev/platform

* Sync flags with platform.txt

* Add support for custom partitions per board

* Add "-fstack-protector" to CCFLAGS

* Use real flash mode and frequency for bootloader

* Use real flash mode and frequency for bootloader

fixes: https://github.com/espressif/arduino-esp32/issues/867

Fixes: https://github.com/espressif/arduino-esp32/issues/866

* Update BLE Library

* Fix SD driver

* Update toolchain

* Update IDF to e5b2c1c

Fixes: https://github.com/espressif/arduino-esp32/issues/860

fix for https://github.com/espressif/arduino-esp32/issues/740

* little fix to WiFiSTA.cpp

Now SmartConfig works! Tested on ESP32

* little fix to WiFiSTA.cpp

Now SmartConfig works! Tested on ESP32

Fixes: https://github.com/espressif/arduino-esp32/issues/803

fixes: https://github.com/espressif/arduino-esp32/issues/613

This reduce net_would_block calls and CPU utilization

Based on http://esp32.net/images/Heltec/WIFI-LoRa-32/Heltec_WIFI-LoRa-32_DiagramPinoutFromBottom.jpg