[Development] Qt Version Compatibility wiki article

[Mitch Curtis]

Hello.

I'm seeking the wisdom of Qt developers in order to improve a wiki article 
that explains Qt's Behaviour/Binary/Source compatibility policy. You can find 
the article here:

http://qt-project.org/wiki/Qt-Version-Compatibility

If you don't have a DevNet account and believe that signing up for one is an 
unacceptable expenditure of your energy, feel free to reply here with your 
suggestions! :D

The idea is to remove all doubt about what can and cannot go into certain 
versions, and examples are particularly useful. Since it seems that there are 
also a lot of exceptions and gotchas, it would be nice to use this article as 
a place to add these.

Cheers.