[REQUEST] Continue #558 (IfcOffsetCurve and all its subtypes)

[SamuilsRulovs]

This issue continues issue #557 and pull request #558

I was trying to implement IfcOffsetCurve and to my mind, I implemented it more or less correctly. You can find a solution in PR #558. However, there were some issues with the getPointOnCurve function which is used for some IfcOffsetCurve subtypes. I couldn't solve this issue, therefore I have decided to comment the code out.

In order to implement IfcOffsetCurve there are several objectives left:

1. Solve an issue regarding getPointOnCurve in different OIP versions (4x1,4x3_rc1 and 4x3_rc4), which disturbs the work of OffsetCurve
2. Create IFC example files