Need colors to show roads without oneway tag and surface tag

[Caboosey]

Feature request:

Need to have additional colors to show when roads do not have oneway tag as oneway=yes or oneway=no

Need to have additional color if surface tag is not set to any.

This will help alert editors to make roads/highways have complete information.

[k1wiosm]

This is going to be hard as I am already running out of colors, specially if I try to make it colorblind-proof as requested on #21.

The only alternative that I see is to be able to activate the colors for one tag at a time.

[micahcochran]

How about placing a series of question marks along the line? Perhaps color them in a red or magenta.

Crude rendering

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EDIT:
Alternatively a dashed red line might work.