Changed - some &*somestdstring.end() to &*somestdstring.begin+somestdstring.size()

          since dereferencing ....end() is undefined
          I realize that most optimizers will do away with the dereference, but some
          debugging libraries won't (in particular VC8.0)


[SVN r27549]

libs/date_time

@@ -1 +1 @@
-Subproject commit 09fc884f2d672b78014e1e184b31c91becd77a60
+Subproject commit 7971e6658afd6c6c123c25f53e65b1e5e529c3bc