A new Shaded presentation flag configured through Datum aspect (NOT as usual Display Mode).
Creation of auxiliary Axis/Point/Plane presentations in Trihedron presentation is removed.
'vtrihedron' DRAW command to change parameters of trihedron is extended to cover whole functionality of AIS_Trihedron.
The following classes are redesignede:
AIS_Trihedron,
Prs3d_DatumAspect.
The followin enumermations are created to manage properties of trihedron:
Prs3d_DatumAttribute,
Prs3d/Prs3d_DatumAxes,
Prs3d_DatumMode
