Max width

[camdez]

Allows the user to specify an optional maximum width for the page break indicator line.

I've personally never been too thrilled about how the lines look when they span my entire screen (nitpicky, I know):

Patch adds an optional maximum width (page-break-lines-max-width), taking care not to be wider than the frame itself):

[purcell]

I can see how some people might prefer this - thanks!

[camdez]

@purcell Awesome. Thanks for the quick review!