CMake support and examples of CMakeLists.txt

I propose a patch for QtPropertyBrowser, that is a collection of CMakeLists.txt files useful to compile examples using cmake, and to propose an example about how to compile QtPropertyBrowser in a cmaked' project without affect sources.
The aim of this bug report is that QtPropertyBrowser isn't so easy to integrate in a cmaked' project and this collection of files can be nice for some Qt developers.

Apply the patch using: path -p1 patch_file_name, from root directory of QtPropertyBrowser after de-tgzipped QtPropertyBrowser archive.

This patch has not been tested under Windows, but it works fine on GNU/Linux system. I'm able to test it also under Windows, if necessary.