text() now accepts strings as keyword args

- if the first positional arg is a string, it will be drawn without any
xml-parsing
- the string can also be passed as a kwarg called `str` leaving the
x/y/width/height values as the only positional args. e.g., text(10,10,
200, str=‘lorem ipsum…’)
- to use inline styles, pass the string as the `xml` kwarg. any tags
that correspond to styles defined with the stylesheet() command will be
rendered with the corresponding font & layout settings
- Text.append supports the same syntax: pass a string as either the
first arg or as an `xml` or `str` kwarg