render function
add an event to the render function
| Parameter | Type | Description | 
|---|---|---|
| canvas | String | name of canvas to add event to render function | 
| name | String | unique name of the render event | 
| event | Function | event to add to render function | 
remove an event from the render function
| Parameter | Type | Description | 
|---|---|---|
| canvas | String | name of canvas to remove event from render function | 
| name | String | name of the render event |