code: function(curve, location, distance) {
  
  		if (_isPoint(curve)) {
  			return {
  				point:curve[0],
  				location:location
  			};
  		}
  
  		var prev = _pointOnPath(curve, location),
  			tally = 0,
  			curLoc = location,
  			direction = distance > 0 ? 1 : -1,
  			cur = null;
  
  		while (tally < Math.abs(distance)) {
  			curLoc += (0.005 * direction);
  			cur = _pointOnPath(curve, curLoc);
  			tally += _dist(cur, prev);
  			prev = cur;
  		}
  		return {point:cur, location:curLoc};
  	}
docs: finds the point that is 'distance' along the path from 'location'.  this method returns both the x,y location of the point and also
  its 'location' (proportion of travel along the path); the method below - _pointAlongPathFrom - calls this method and just returns the
  point.