Width option has some problems

[liborw]

Hi,

first thanks for this plugin! I have found couple of problems with the width option. The label is always a bit wider than set width and also the caps are not taken into account, both combined makes it quite hard align labels.

[gregdavill]

Thanks for taking a bit of a deeper look at this.

I kind of tweaked some scaling factors a bit so the widths kinda matched up to mm. But it looks like it's a bit off.
Different end caps also will always increase the width currently.