Introduce a "Fit Text Width" zoom mode

This also changes how the other "fit" modes work: We now zoom in to the fit the
max pagesize of the currently shown pages. Previously we zoomed in to the max
pagesize of the entire document.

The page counter in the lower left of Words' window now show the scroll position
and not the cursorposition. Previously it was a weird mix

The page counter also now shows ranges so that if pages 3,4,5 are shown, the counter
says "3-5 of 47"

REVIEW: 108420