More faithful mapping of border line thicknesses.

This time based on how they get printed on paper, not how they look
on screen.

Change-Id: I61a217822229f843de3e89e96cf58b273f2cd8ac
Double line looks a bit too apart.

Change-Id: I14676b6e8282a76d0be9dc0cc78e01837726e494
Revise the line patterns further. Now they look satisfactory to my eye.

Change-Id: I27f4e11bceac25c10de28a866bdcec9576027582