CMakeLists update for external HDF5 and out of source build

Updated statismo-config.cmake and CMakeLists.txt in order to retrieve the actual path of HDF5 include dirs also in case of external HDF5 libraries. 
Explicitly defined STATISMO_ROOT_DIR in order to compile the examples also in case of out of source build.
Explicitly defined the order of include directories in order to avoid conflicts when loading H5cpp.h
Tested on Windows 7- VS 2008. 
(possible problems with line endings in the present commit)