Trailing space after sparkline

[PKlknr]

Hi, the svg for sparklines is a bit wider than the paths - this becomes apparent for example when adding a border:

This seems to be due to Contex.Sparkline.draw calculating the viewbox width as sparkline.length + 1. Without looking too deeply, changing that to length - 1 seems to fix the issue.

PS: While writing this I noticed the same fix in 56f7ec7 Maybe that could be cherry-picked?

Thanks for this very cool lib!

[mindok]

I'll take a look a little later - got some crunchy deadlines on at the moment. There are a few improvements to sparklines in the PR that @fceruti put together, so makes sense to pull that in.