Make the unordered constructors from allocators explicit.

And clean of the FNV-1 example & documentation a little.

Merged revisions 47085,47132,47143-47146 via svnmerge from 
https://svn.boost.org/svn/boost/trunk

........
  r47085 | danieljames | 2008-07-04 23:57:20 +0100 (Fri, 04 Jul 2008) | 4 lines
  
  Require explicit conversion from allocators.
  
  (Not what it says in the draft standard, but I think that might be a defect).
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  r47132 | danieljames | 2008-07-06 13:41:09 +0100 (Sun, 06 Jul 2008) | 2 lines
  
  'Bias' should be 'basis'.
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  r47143 | danieljames | 2008-07-06 22:06:52 +0100 (Sun, 06 Jul 2008) | 1 line
  
  Clean up the FNV-1 comments.
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  r47144 | danieljames | 2008-07-06 22:07:31 +0100 (Sun, 06 Jul 2008) | 1 line
  
  I've only got one hash function for release, so no need for its own directory.
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  r47145 | danieljames | 2008-07-06 22:08:11 +0100 (Sun, 06 Jul 2008) | 1 line
  
  Remove the hash_functions directory (for now).
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  r47146 | danieljames | 2008-07-06 22:29:47 +0100 (Sun, 06 Jul 2008) | 1 line
  
  Update the docs for the new location of FNV-1.
........


[SVN r47150]

doc/hash_equality.qbk

@@ -23,8 +23,8 @@ but not the equality predicate. For example, if you wanted to use the
 [import src_code/dictionary.cpp]
 [case_sensitive_dictionary_fnv]
 
-An example implementation of FNV-1, and some other hash functions are supplied
-in the examples directory.
+There is an [@../../libs/unordered/examples/fnv1.hpp implementation
+of FNV-1] in the examples directory.
 
 If you wish to use a different equality function,
 you will also need to use a matching hash function. For

doc/ref.xml

@@ -181,7 +181,7 @@ file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
               <para>The copy constructor. Copies the contained elements, hash function, predicate, maximum load factor and allocator.</para>
             </description>
           </constructor>
-          <constructor>
+          <constructor specifiers="explicit">
             <parameter name="a">
               <paramtype>Allocator const&amp;</paramtype>
             </parameter>
@@ -928,7 +928,7 @@ file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
               <para>The copy constructor. Copies the contained elements, hash function, predicate, maximum load factor and allocator.</para>
             </description>
           </constructor>
-          <constructor>
+          <constructor specifiers="explicit">
             <parameter name="a">
               <paramtype>Allocator const&amp;</paramtype>
             </parameter>
@@ -1685,7 +1685,7 @@ file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
               <para>The copy constructor. Copies the contained elements, hash function, predicate, maximum load factor and allocator.</para>
             </description>
           </constructor>
-          <constructor>
+          <constructor specifiers="explicit">
             <parameter name="a">
               <paramtype>Allocator const&amp;</paramtype>
             </parameter>
@@ -2483,7 +2483,7 @@ file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
               <para>The copy constructor. Copies the contained elements, hash function, predicate, maximum load factor and allocator.</para>
             </description>
           </constructor>
-          <constructor>
+          <constructor specifiers="explicit">
             <parameter name="a">
               <paramtype>Allocator const&amp;</paramtype>
             </parameter>
@@ -3062,4 +3062,4 @@ file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
         </class>
       </namespace>
     </header>
-  </library-reference>
+  </library-reference>

doc/src_code/dictionary.cpp

@@ -6,7 +6,7 @@
 #include <boost/unordered_map.hpp>
 #include <boost/detail/lightweight_test.hpp>
 #include <boost/algorithm/string/predicate.hpp>
-#include "../../examples/hash_functions/fnv-1.hpp"
+#include "../../examples/fnv1.hpp"
 
 //[case_insensitive_functions
     struct iequal_to