Boost.Range updated the return types of various algorithms to improve consistency. This is to address a specific request made during the formal review of Boost.RangeEx.

[SVN r61211]

libs/range

@@ -1 +1 @@
-Subproject commit cab01e8ba3d34344f7a7780843ea79e2a89f99b1
+Subproject commit 350a1f8bfc39b34cb36c86c99da1d7ac0dd5f6b1