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

* 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

The .build.board=xx proptery is used for generating a macro named "ARDUINO_xxx".

C macro names should never have a "-" sign.

* current: ARDUINO_NodeMCU-32S
* should be: ARDUINO_=NodeMCU_32S

* fix NodeMCU-32S .build.board property

The .build.board=xx proptery is used for generating a macro named "ARDUINO_xxx".

C macro names should never have a "-" sign.

* current: ARDUINO_NodeMCU-32S
* should be: ARDUINO_=NodeMCU_32S

* fix compiler flags to be compatible to ESP8622/Arduino

see also "fix NodeMCU-32S .build.board property" #812 (https://github.com/espressif/arduino-esp32/pull/812#issuecomment-341990261)

`-DARDUINO_BOARD={build.board}` **is missing**

* Revert "fix NodeMCU-32S .build.board property"

This reverts commit ea57b1496a2e87d3977a31a29a4cf7d63216f008.

* 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.

Localized versions of Linux systems use Unicode characters in the names of standard directories like "Downloads".

use minimal partitions

* Forward client certificate to wificlient secure

* remove comment

* Update boards.txt

* Create pins_arduino.h

* Update IDF to 9274814

* Fix error in i2c and Arduino

Correct 10bit Device address handling.

Add initial handling for long I2C reads.

The existing code did not follow protocol with 10bit addressed devices.  Per _Philps/NXP Semiconductors UM10204 I2C-bus specification and user manual Rev. 6 4April2014_ pg.15 3.1.11 10-bit addressing:
~The first seven bits of the first byte are the combination of 1111 0xx of which the last two bits (xx) are the two Most-Significant Bits (MSB) of the 10-bit address; the eighth bit of the first byte is the R/!W! bit the determines the direction of the message~