Option to let user choose to follow right-hand rule or not

[johachi]

Problem

Right now, the polygon returned always has its coordinates ordered counter-clockwise. It is currently not possible to get the coordinates ordered clockwise. Examples when the user might want to have the coordinates clockwise:

• IF the user wants to create a hole in a shape, as specified here
• When other parts of the system require them to be clockwise (the old informal specifications also allowed for clockwise polygons)

Proposed Solution

Add option to allow coordinates to be arranged clockwise.

This should be done after #13 has been solved.

Proposed argument:

option = { useLeftHandRule: false }

option = { useLeftHandRule: true }

Default value should default to false when missing.