About an export dialog for all of rendering

[micheus]

Yeah, it has been boring make all these POV tests passing by Render option dialog.
I don't think we can change the way the material dialogs works today, but I believe we can do something about the start render action. I would prefer change the material settings and just hit a key or press a button to render the scene using the latest Render settings. Currently we need select the proper render item in the menu; enter in the option dialog and hit ok; be prompt about rewrite the old file and hit ok. It's too much steps.

I'm still thinking about this.