Merge: lib: move some examples/* into specific subdirectories of their lib

examples/ starts to become a mess.
So move the simple examples of lib into an `example` subdirectory of the lib.

But I am not really sure that it is a good idea.

Before: 132 projects, now 120 projects.

Pull-Request: #793
Reviewed-by: Alexandre Terrasa <alexandre@moz-code.org>