Add support for including .ctrl with documentation output

I recently ran into a use case where I needed to grab .ctrl images and their descriptions (and ideally tooltip text) and dump them into a documentation package for sharing with colleagues. Antidoc seemed like it would be the perfect way to do this, however Antidoc does not detect .ctl files or handle them in any way (they are ignored).

The use case was fairly trivial: User wanted to have documentation of various customized common controls and indicators used in our application so that they could have a pre-defined legend and also for making application wide feedback more accessible with respect to various UI components.

I think that this is something of a tricky feature to define/resolve in that there are .ctl files that are just used as type defs with no cosmetic value, and while there are .ctl that are clearly UI oriented (strictly typed or xctl), there are many use cases for UI oriented non-strictly typed type defs. Based on this, I think it would be critical to have exclusions from antidoc via masks or similar for control documentation.

Would recommend some form of this to become a future supported feature for enabling more comprehensive documentation of project components.