Override for clarity
Fix doc bug
Less code

Since out meters per unit conversion table is a bit spare, prefer the configured conversion.
Merge pull request #815 from tschaub/override

Override for clarity
Add method to determine winding order of linear rings
Store rings so exerior is clockwise and interior is counter-clockwise

KML and WKT don't specify a winding order, so we write those out in CW/CCW order (for exterior/interior).  GML references ISO 19107 that specifies CCW/CW, so we serialize in that winding order.

Having hand generated all this GML data the first time around, I reserve the right to modify it for the tests.