Make include sources copied when configuring the project

[asmodehn]

The include directory should be copied inside the build directory when the project is configured through cmake and not when build is successful.
It will allow upper project to build even if a dependency was not build successfully.
Of course the link will failed but the user will be able to check is code (syntax and such) and so submit it to subversion even if he can't run it.
Data copy mustn't change.