* Retrieve some code from what has been done on the ESP8266. Clarify a bit the signification of several bytes in the response.

* Add the type and class as members of the DNS class for an eventual future use.

* Clarify the sense of a magic number present in DNS server.

* A bit of aesthetics for the DNS server.

* Add a structure for the DNS question, use it DNS server to store the question data and to create the DNS answer from scratch.

* Added a lastError method to WiFiClientSecure so that a connection error from mbedTLS can be retrieved if connection fails (and then presented to a user).

* Changed to dos CRLF

* Made buffer size a const\nMore cleanup to match source

* 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...

* 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.

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.

* Update BLE Library

* Fix SD driver

* Update toolchain

* Update IDF to e5b2c1c

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

* ArduinoOTA would stop receiving any packets if the port received a zero-length UDP packet, commonly sent by network scanners like nmap. Fixed to flush() after every call to parsePacket(), even if read length is 0.

Additionally, added length checking to fix a potential buffer overflow in parseInt().

Finally, added an end() method that stops the OTA listener and releases resources.

* Only end MDNS in end() if mdns mode is enabled.

* Forward client certificate to wificlient secure

* remove comment

Missed definition

Fixes: https://github.com/espressif/arduino-esp32/issues/749

Works even when single core mode is selected

* Update IDF to de750e9

* Add BLE Library submodule

* ESP32 default port in comment

* ESP32 default hostname.

* Create ledcWrite_demo_ESP32_RGB.ino

adding the public domain example ledcWrite_demo_ESP32.ino to this repo.  Added RGB to the name for people searching, added some comments, and renames things to make a bit more sense.

* Update ledcWrite_demo_ESP32_RGB.ino

renamed to ledcWrite_RGB.ino and added a couple more comments based on https://github.com/espressif/arduino-esp32/issues/689

* Rename libraries/ESP32/examples/AnalogOut/ledcWrite_demo_ESP32_RGB/ledcWrite_demo_ESP32_RGB.ino to libraries/ESP32/examples/AnalogOut/ledcWrite_RGB/ledcWrite_RGB.ino

Renamed.

* Addition of a i2cReset method and timeout handling for the case where the i2c hardware FSM (state machine) gets stuck in a busy state.

* Use newly added i2cReset function within the wire library.

* Add example to update ESP32 via SD card

* Delete update.bin from sd upon finishing update

* remove precompiled binary from example

* Check whether update.bin is a file