[CMake] Add Find*.cmake to cmake package

[Raphaël Gertz]

Hi,

I was looking for FindGTK2.cmake cmake module, and discovered that it's not 
provided with cmake2.6.

May you plz add it and stables modules from this source :
https://svn.opensync.org/branches/3rd-party-cmake-modules/modules/

It would be great to add the other usefull one too like FindGTHREAD2.cmake and 
other.

It would simplify a lot cmake developpement.

Thank's