Big merge of Boost.CircularBuffer :

* Full merge of QuickBoock documentation from Paul A. Bristow
* Merged rvalue references support with tests and documentation (fixed #7888)

[SVN r85510]

libs/circular_buffer

@@ -1 +1 @@
-Subproject commit 6998f28fda3376b37630d01ff0112b44a0428b4c
+Subproject commit 6eb5fd4a3d8c470262284128097422f50b0bdf11