Set a property to equal another property

# Scope
To set a canvas width to equal its client width, you need to do:
```JavaScript
Z('canvas').width(Z('canvas').clientWidth()[0]);
```
Tere should be an easier way to do this.

# Suggested Solution
```JavaScript
Z('canvas').width(Z.clientHeight);
```
This would involve storing the current values in Z, as this would need to work for groups of canvases as well.

