Splitting module size into width and height

```
To support a matrixcode format like PDF417, you need to be able to specify a 
different width and height for the module size. For now, modules are considered 
to be square and thus width and height are equal.
Module size needs to be split in a width and a height.
```

Original issue reported on code.google.com by `petermi...@gmail.com` on 28 Mar 2011 at 12:47
