fixed bug with vertical lines between columns

In putting together a wiki example, I came across a bug with the vertical bars between columns. If the penultimate slot for a bar had a bar, as with rrr|r, then you would actually see something that looked like rrr|r|. The change at line 353 fixes this. The change at line 229 makes it so that, for example, in |r|r|r|, the inner bars do not end up looking twice as thick as the outer bars.