Add instructions for using as IDF component

Fixes issue where switch will not properly trigger if Arduino is used
in IDF as component.
See
https://github.com/espressif/arduino-esp32/issues/83#issuecomment-265326
071

- Link to Windows instructions
- Update instructions for Linux and Mac

Fix formatting and numbering

fixes: https://github.com/espressif/arduino-esp32/issues/76

need close(sockfd) before sockfd = -1, "_connected = false and close socket" means stop() function. (#73)

fixes: https://github.com/espressif/arduino-esp32/issues/72

currently ```esp_wifi_init``` have to be called in ```app_main``` or
WiFi will fail to boot. When possible to boot later, code will be moved
into ```_esp_wifi_start``` to be executed when necessary

use driver/gpio for now.

fixes: https://github.com/espressif/arduino-esp32/issues/66

fixes: https://github.com/espressif/arduino-esp32/issues/69

IDF Options:
- Autostart Arduino (implements app_main)
- Disable HAL locks
- Set HAL debug level
- Auto-connect STA if configured (else will connect after WiFi.begin())

fixes: https://github.com/espressif/arduino-esp32/issues/57

related to [issue
53](https://github.com/espressif/arduino-esp32/issues/53)

Fixes: https://github.com/espressif/arduino-esp32/issues/54

fixes: https://github.com/espressif/arduino-esp32/issues/55

* Add "Noduino Quantum" board

* change the value of build.board from Quantum to QUANTUM

NOTE: UART1's default pins can be used only when SPI Flash is DIO

thanks @Ladyada

thanks @Ladyada

thanks @Ladyada

- Shorten filenames
- Add log_printf with mutex locking to play nice with Serial and two
cores