Method StlAPI_Writer::Write() is reimplemented to write triangulation directly, without conversion to StlMesh_Mesh.
New DRAW command "tessellate" is added to generate rapidly triangulation of prescribed size (on surface).
Command "tricheck" is protected to deal correctly with triangulation without UV data.
New tests added: perf de bug26338_1 and _2; bugs stlvrml bug26338
Correction of testing environment