Code refactoring of BRepGProp_Sinert and BRepGProp_Vinert classes.
- All static variables have been removed.
- Common functionality connected with Gauss integration has beem moved from BRepGProp_Sinert and BRepGProp_Vinert classes to the new BRepGProp_Gauss class.
Slight changes in the comments.
Fix compilation error.
Fix Sinert errors. Rebased on new master.
Elimination of constant conditional expression warnings.
Small fix in comment.