SD card support

[thijstriemstra]

Reading/writing to an SD card would be nice (or maybe as an example).

[thebigpotatoe]

Interesting idea. Might be a little bit out of scope for what I envisioned for this library originally, but it certainly makes sense to use an SD card also.

Having a quick look at the SD API it seems it shares similar function calls which is cool. Incorporating that may be as easy as changing some of the macros at the top of the library header file.

Currently I don't own and have never operated a esp8266 or esp32 with an SD card slot, and I don't know when I will. So to implement this will probably be down the track. But pull requests are welcome!

[thijstriemstra]

I'll be trying this in near future and let you know how it goes; http://www.iotsharing.com/2017/05/how-to-use-arduino-esp32-to-store-data-to-sdcard.html

[thebigpotatoe]

Awesome, let us know how it goes. If it works and you're happy to play around with the library let us know. It might tempt me to buy a few SD modules to do this.

[thijstriemstra]

It might tempt me to buy a few SD modules to do this.

Sweet. They're dirt cheap ;)