0024683: Convertation of the generic classes to the non-generic. Part 1

0024683: Convertation of the generic classes to the non-generic. Part 1

Generic classes from "BRepApprox" package:
    "BRepApprox_ApproxLineGen" and "BRepApprox_SurfaceToolGen" converted to the non-generic classes "BRepApprox_ApproxLine" and "BRepApprox_SurfaceTool".
Generic classes from "BRepBlend" package:
    "BRepBlend_HCurve3dToolGen" and "BRepBlend_HCurve2dToolGen" converted to the non-generic classes "BRepBlend_HCurve3dTool" and "BRepBlend_HCurve2dTool".
Generic classes from "Blend" package:
    "Blend_Extremity", "Blend_Line" and "Blend_PointOnRst" moved to the corresponding non-generic classes "BRepBlend_Extremity", "BRepBlend_Line" and "BRepBlend_PointOnRst" to "BRepBlend" package.

And some other minor changes were done.
Field "myPntOn2S" was deleted from "BRepApprox_ApproxLine" class. Therefore BRepApprox_ApproxLine::Point(...) method was a little changed.