Changed
- Library API: the `page_size` and `layout` arguments can now be specified either as a string (just like in the command line interface)
or as a sequence of two numbers (for example, `page_size='LETTER', layout='2x3'` is equivalent to `page_size=(72 * 8.5, 72 * 11), layout=(2, 3)`)
- CLI: error message includes the name of the underlying exception's class