Make C++11 fusion::vector more consistent with C++03 fusion::vector

- Construct from elements is enabled iff each argument is_convertible to
    corresponding element.
  - Construct from sequence is enabled iff the single argument is a fusion
    sequence.
  - C++11 vector and tuple also disable construct from sequence that are
    shorter than the destination. C++03 gives incorrect is_convertible
    responses in this situation and fails to compile if that constructor is
    used; C++11 can have instantation errors in
    and_<is_convertible<U, T>...> without the additional check.
  - C++11 tuple and vector support truncation conversion and assignment like
    all other sequences.

test/sequence/deque_copy.cpp

@@ -13,10 +13,30 @@
 #define FUSION_SEQUENCE deque
 #include "copy.hpp"
 
+using namespace test_detail;
+
+// c++11 deque has bug, cannot properly copy-assign from a const value
+template <typename T>
+struct skip_const_lvalue_assignment
+{
+    template <typename Source, typename Expected>
+    bool operator()(Source const& source, Expected const& expected) const
+    {
+        return
+            run< can_implicit_construct<T> >(source, expected) &&
+            run< can_construct<T> >(source, expected) &&
+            run< can_rvalue_assign<T> >(source, expected) &&
+            run< can_lvalue_assign<T> >(source, expected);
+    }
+};
+
 int
 main()
 {
-    test();
+#if defined(BOOST_FUSION_HAS_VARIADIC_DEQUE)
+    test<skip_const_lvalue_assignment>();
+#else
+    test<can_copy>();
+#endif
     return boost::report_errors();
 }
-