0027651: Add projection support in sewing pcurves handling

0027651: Add projection support in sewing pcurves handling

1. BRepLib.hxx, BRepLib_1.cxx - implementation of method SetPCurve(...), which can build new pcurve by projection, if pcurve to be set is not  satisfied by tolerance criterium.

2. BRepBuilderAPI_Sewing.cxx - modification of method SameParameterEdge(...) using new method SetPCurve(...)

3. BRepTest/BRepTest_BasicCommands.cxx - implementation Draw command SetPCurve

4. Approx_ComputeCLine.gxx, BRepOffsetAPI_DraftAngle.cxx, ProjLib_ProjectedCurve.cxx - small modification to fix regression.

5. Modification of tests according to current behavior of sewing algorithm.

6. Test case added
 bugs/modalg_6/bug27651

7. dox/user_guides/draw_test_harness/draw_test_harness.md
Documentation update.