Changed regex_token_iterator to return a sub_match rather than a std::string (it's more efficient).

[SVN r20613]

libs/regex

@@ -1 +1 @@
-Subproject commit de9338cedf15236c1a53668e21113420b9bb5cfb
+Subproject commit 23f71d7727aa140c165fe34b008a1d6a7a6f12ff

tools/bcp

@@ -1 +1 @@
-Subproject commit adbd8bc72246ee4f6f83e2f7c2846836d38de2e5
+Subproject commit 526d221b6cc7ae8eee154c8642522d6630c5d18a