Geometry_Engine: Method correcting Arcs

#### Description:

Some Arcs from Rhino have switched angles. E.g Instead of having StartAngle = 0 and EndAngle = 1 they have StartAngle = -1 and EndAngle = 0. Is it justified by anything?
Some of my methods base on that an arc has a StartAngle = 0 so I just wrote simple check correcting it:
`if(arc.StartAngle != 0)`
`{`
`arc.CoordinateSystem = arc.CoordinateSystem.Rotate(arc.CoordinateSystem.Origin, arc.CoordinateSystem.Z, arc.StartAngle);`
`arc.EndAngle = -arc.StartAngle;`
`arc.StartAngle = 0;`
`}`

It works like this:
Geometrically those two arcs are identical.
Do you think it is worth adding to the engine?