Added settings for
* doubletap to reveal
* showing/ hiding zeros
* enabling/ disabling counting down numbers on mark
* showing/ hiding an outline around the playing field
* hiding islands of marked mines once they can't be wrong

Also, a slider to adjust how much your finger can move before it isn't considered a press anymore.

Added an explanation for all the settings

Added "Purist" mode where the reveal is more conservative but accurate to the 2D equivalent

Special thanks to d-albrecht for his extensive testing and feedback :)
