Fix tutorial example (trac #11017)

Extract example into a C++ file, so that it can be tested, unfortunately this
means that it no longer links to the reference documentation.

doc/samples/tutorial.cpp

@@ -0,0 +1,27 @@
+#include <boost/container_hash/hash.hpp>
+#include <vector>
+#include <algorithm>
+#include <iterator>
+#include <cassert>
+
+//[ get_hashes
+template <class Container>
+std::vector<std::size_t> get_hashes(Container const& x)
+{
+    std::vector<std::size_t> hashes;
+    std::transform(x.begin(), x.end(), std::back_inserter(hashes),
+        boost::hash<typename Container::value_type>());
+
+    return hashes;
+}
+//]
+
+int main() {
+    std::vector<int> values;
+    values.push_back(10);
+    values.push_back(20);
+
+    std::vector<std::size_t> hashes = get_hashes(values);
+    assert(hashes[0] = boost::hash<int>()(values[0]));
+    assert(hashes[1] = boost::hash<int>()(values[1]));
+}

doc/tutorial.qbk

@@ -3,6 +3,9 @@
  / Distributed under the Boost Software License, Version 1.0. (See accompanying
  / file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) ]
 
+[quickbook 1.7]
+[import samples/tutorial.cpp]
+
 [def __multi-index-short__ [@boost:/libs/multi_index/doc/index.html
     Boost.MultiIndex]]
 
@@ -39,15 +42,7 @@ To use [classref boost::hash] directly, create an instance and call it as a func
 For an example of generic use, here is a function to generate a vector
 containing the hashes of the elements of a container:
 
-    template <class Container>
+[get_hashes]
-    std::vector<std::size_t> get_hashes(Container const& x)
-    {
-        std::vector<std::size_t> hashes;
-        std::transform(x.begin(), x.end(), std::insert_iterator(hashes),
-            ``[classref boost::hash]``<typename Container::value_type>());
-
-        return hashes;
-    }
 
 [endsect]