Replace reinterpret_cast with static_cast.

Conversion between pointers of unrelated types `Source` and `Target`
can be done with `static_cast` => IMO should be done with `static_cast`
(in order not to give the impression that `reinterpret_cast` really is needed):

  `T *ptr_target = static_cast <T *> (static_cast <void *> (ptr_source));`

IMO `reinterpret_cast` should be used for pointer-to-integral and integral-to-pointer
conversions (only).

include/boost/type_traits/integral_constant.hpp

@@ -61,7 +61,7 @@ namespace boost{
       {
          static const char data[sizeof(long)] = { 0 };
          static const void* pdata = data;
-         return *(reinterpret_cast<const mpl::integral_c<T, val>*>(pdata));
+         return *static_cast<const mpl::integral_c<T, val>*>(pdata);
       }
       BOOST_CONSTEXPR operator T()const { return val; }
    };
@@ -81,7 +81,7 @@ namespace boost{
       {
          static const char data[sizeof(long)] = { 0 };
          static const void* pdata = data;
-         return *(reinterpret_cast<const mpl::bool_<val>*>(pdata));
+         return *static_cast<const mpl::bool_<val>*>(pdata);
       }
       BOOST_CONSTEXPR operator bool()const { return val; }
    };