move Get_arithmetic_kernel specialization into MP_Float.h
reorder declaration of to_double(Sqrt_extension<MP_Float>)
Sqrt_extension need specialization of Real_embeddable_traits
and Algebraic_structure_traits.
by namespace CGAL { and } //namespace CGAL. in all .h and .cpp files
in a directory.
Apply it to all packages in the trunk
Remove macro definition from the config.h file.