[Development] C++11 for Examples

[Guido Seifert]

> Make it unconditional and let people disable with -nomake tests or 
> -no-compile-examples if they have older compilers.

Why not make different example categories? One category, which has the same policies as Qt itself, i.e. it compiles
with all the compilers Qt supports. Additionally a category, which uses all new stuff C++11 stuff. And perhaps an 
experimental cat, which is insane and requires C++2x <--- ok, slight exaggeration.
Then the cats could be disabled with  -no-compile-examples, -no-compile-examples-modern, -no-compile-examples-insane.

I was in several projects where I have been told: Don't use this feature, don't use that feature. Sometimes the reasons
where understandable, sometimes I had the feeling the reason was the project manager was stuck in 98 and did not understand
anything beyond that. 

Now it is not Qt's task to teach modern C++, but if examples using those new features help/convince other people to migrate,
it also helps Qt.

Guido