[Mapcss] width: thinnest

[Sebastian Klein]

Hi,

in swing you can draw a very fine line (much thinner than 1 px).

This is useful if you have a focus on certain features. If all 
unimportant ways are drawn in this style, the map looks clear, but still 
complex.

It might not be available for every graphics lib, so support should be 
optional.

I added it to the wiki, maybe there is a better wording for the keyword?


Sebastian