Given a URI, returns the base path of the URI.
    
    
    
    
    
    
        
| Name | Type | Default | Description | 
|---|---|---|---|
| uri | String | The Uri. | |
| includeQuery | Boolean | false | optional Whether or not to include the query string and fragment form the uri | 
Returns:
    The base path of the Uri.
        
    
    
Example:
// basePath will be "/Gallery/";
var basePath = Cesium.getBaseUri('/Gallery/simple.czml?value=true&example=false');
// basePath will be "/Gallery/?value=true&example=false";
var basePath = Cesium.getBaseUri('/Gallery/simple.czml?value=true&example=false', true);