0024622: Add method to AIS_TexturedShape class to assign texture data directly from byte stream

Added methods to specify Image_PixMap as texture source to AIS_TexturedShape and Graphic3d_TextureRoot.
Modified internal class MeshVS_ImageTexture2D, originally used for the purpose of sourcing texture as Image_PixMap.

AIS_TexturedShape class:
- Get rid from cdl declaration.
- Remove unused and uninitialized field myDeflection / method Deflection().
- Improve class documentation.
- Use Graphic3d_NOT_2D_UNKNOWN instead of -1.
- Use myIsCustomOrigin and myToScale flags to use/ignore custom values.

src/Graphic3d/Graphic3d_TextureMap.cxx

@@ -27,6 +27,16 @@ Graphic3d_TextureMap::Graphic3d_TextureMap (const TCollection_AsciiString& theFi
 {
 }
 
+// =======================================================================
+// function : Graphic3d_TextureMap
+// purpose  :
+// =======================================================================
+Graphic3d_TextureMap::Graphic3d_TextureMap (const Handle(Image_PixMap)&   thePixMap,
+                                            const Graphic3d_TypeOfTexture theType)
+: Graphic3d_TextureRoot (thePixMap, theType)
+{
+}
+
 // =======================================================================
 // function : EnableSmooth
 // purpose  :