Math.Quaternion: Fix forward declarations of quaternion.

See https://github.com/boostorg/math/issues/99

include/boost/math/quaternion.hpp

@@ -11,6 +11,7 @@
 #define BOOST_QUATERNION_HPP
 
 #include <boost/config.hpp> // for BOOST_NO_STD_LOCALE
+#include <boost/math_fwd.hpp>
 #include <boost/detail/workaround.hpp>
 #include <boost/type_traits/is_convertible.hpp>
 #include <boost/utility/enable_if.hpp>

include/boost/math_fwd.hpp

@@ -9,8 +9,6 @@
 #ifndef BOOST_MATH_FWD_HPP
 #define BOOST_MATH_FWD_HPP
 
-#include <boost/cstdint.hpp>
-
 namespace boost
 {
 namespace math
@@ -22,13 +20,6 @@ namespace math
 template < typename T >
     class quaternion;
 
-template < >
-    class quaternion< float >;
-template < >
-    class quaternion< double >;
-template < >
-    class quaternion< long double >;
-
 // Also has many function templates (including operators)