Add toggle to enable/disable wireframe overlay on meshes selected in Viewer

[bentoogood]

depends on #114

[johnhaddon]

Quick question on this one - will there be some other way to know what is selected or do we actually want them to be drawn exactly like everything else? What's the use case for this one? It's been a while since we made it so I'm a little foggy...

[bentoogood]

Yeah... I'm not totally sure either.

When I skim read this to put it on this milestone, I took it to be 'toggle (globally) between wireframe and shaded mode in opengl'

Maybe there was some good reason, but it's not coming to me right now...

[johnhaddon]

Do we have a ticket for opengl shading overrides in general? Seems like that would make a lot more sense than this one...

[johnhaddon]

Closing this one since the global wireframe/shaded toggle is already available, and no-one seems to remember if this ticket is referring to the selection specifically, and if it is, why.