Merged in smart_ptr changes from the sandbox/boost0x branch created for

BoostCon '09.  This adds move semantics to weak_ptr and intrusive_ptr.


[SVN r52937]

libs/smart_ptr

@@ -1 +1 @@
-Subproject commit 4b4a62513f0bf33f86520fb737869fa269b61d3f
+Subproject commit fc1254381487aa657b674ba626b273a822983ad0