Visualizing the meshes with wireframe mode

[cerdogan]

At the moment, grip supports visualizing the wireframe mode (only the lines of the mesh triangles, no surfaces) if the material properties are set in the mesh files (i.e. dae) in applyMaterial() function in OpenGLRenderInterface.h.

However, one might want to visualize the wireframe, without wanting to change .dae files - for instance a button in the menubar or something just like solidworks.

It would be nice to provide this interface to the users who are interested in center of mass of objects which are likely to lie within the meshes.