prepend '::' in front of type names that have namespaces
prepend '::' in front of type names that have namespaces

Types might be used in some template specializations. Adding ::
will help avoiding name clashes issues between namespaces.

For instance, the base::Time type, if used in

namespace RTT {
  namespace corba {
  template<> AnyConvertion< base::Time > {}
  }
}

will fail to compile as RTT::base exists. However,

namespace RTT {
  namespace corba {
  template<> AnyConvertion< ::base::Time > {}
  }
}

will work

doudou/modelkit-component,doudou/modelkit-component