Cardinal Directions for Roofs and Misc Roof Fixes

[justinormont]

Additions:

• Add cardinal directions (N, S, WNW, ...) processing to roofs

Fixes:

• Remove extraneous 'round' from list
• Fix false warning for roof.direction='0' (north-facing) for skillion roofs

Closes https://github.com/Beakerboy/OSMBuilding/issues/60

[Beakerboy]

Could you add a test for the new cardinal direction code? And one that demonstrates that a building with a north roof does not produce an entry in the error log, but one with a missing direction does?

[Beakerboy]

I submitted a pull request to your branch. Please review it and let me know what you think. I refactored your function to make is shorter and created a unit test for it. It still needs a test for the message in the error log.