Implement new mechanism to handle critical/dangerous permissions

[codeanticode]

Register handler method with requestPermission(“the.name”, “callbackName”), with the callback being passed true or false according to the outcome of the permission request operation:

void setup() {
  requestPermission("android.permissions.BODY_SENSORS", "initSensors");
}

void initSensors(boolean granted) {
  if (granted) {
    // init sensors
  } else {
    // error handling
  }
}

[codeanticode]

Implemented with 80601c4 and 72413b5

Note that all callback methods will be called as many times as they set with requestPermission(), even if they to several permissions from the same group.