code: function(p1, p2, props) {
  		if(!props) {
  			props = ['x', 'y'];
  		}
  		var x = p2[props[0]] - p1[props[0]];
  		var y = p2[props[1]] - p1[props[1]];
  		return sqrt((x * x) + (y * y));
  	}
docs: distance
  @param {type} p1
  @param {type} p2
  @returns {Number}