IFC4.3 Legacy Issues part 2

EXPRESS function IfcBaseAxis has following code inside:

`
Factor := IfcDotProduct(Axis2, U[2]);

IF (Factor < 0.0) THEN (* Here is an untolerant comparison for REAL value *)

U[2].DirectionRatios[1] := -U[2].DirectionRatios[1];

U[2].DirectionRatios[2] := -U[2].DirectionRatios[2];

END_IF;
`

we've faced with issue when input vectors have 'slightly' negative values like:
#8130=IFCDIRECTION((1.,0.,-4.27642353614751E-50));
#8131=IFCDIRECTION((-4.48534439404616E-68,1.,0.));
so this comparison gets negative Factor, and the result of IfcBaseAxis is also incorrect.

This couldn't be solved on the interpretation level as specification says comparisons <, > etc. should be performed without precision taken into account. Here probably the way is to use tolerant comparisons in this and all similar places within schema, as we know the context of comparison.

Start with the EXPRESS function IfcBaseAxis and the supplied IfcDirection vectors, then review similar REAL comparisons throughout the schema. Confirm the interpretation-level limitation described in the issue and define tolerant comparisons that prevent the incorrect IfcBaseAxis result for slightly negative values.

Written by the indexing model from the issue text.