Add collection of games hosted on Github build with braingdx

[shoeoffhead]

Motivation

Developers are much more motivated giving braingdx a try if there were several good examples of mid-sized games written with braingdx for which the source code is available.

[bitbrain]

@shoeoffhead There actually is: https://github.com/bitbrain/braingdx#games-created-with-braingdx

Or do you mean something else?

[shoeoffhead]

I have seen those. But as a hobby developer I would like to look at source code. Is the code available for those games?