stretch style unimplemented

[jasonrclark]

From http://shoesrb.com/manual/Styles.html#:stretch

:stretch » a string
For: banner, caption, code, del, em, ins, inscription, link, para, span, strong, sub, sup, subtitle, tagline, title.

Sets the font stretching used for a text object.

Possible settings are:

"condensed" - a smaller width of letters.
"normal" - the standard width of letters.
"expanded" - a larger width of letters.

Aim would be to match the general behavior of Shoes 3 with this option