Plotting Points in South West Quadrant

Line 471 of GoogleMapAPI.php looks problematic

```
            if(($obj->getLatitude() > 0) || ($obj->getLongitude() > 0)) {
```

I assume this is meant to be checking for null points.  However if both points are negative, then this will also fail the check.  As such I think it should be != 0 instead of >0 for the coordinate checks above

Regards

Gordon 
