Merging support for by_key operations.

diff --cc ChangeLog
index 5ac1b756252ae7ff8848a98e1ba27241800fdf80,5ac1b756252ae7ff8848a98e1ba27241800fdf80..cfb713a66d82707519fb2fa2418978635edac92f
--- 1/ChangeLog
--- 2/ChangeLog
+++ b/ChangeLog
@@@ -1,3 -1,3 +1,4 @@@
++  * Added support for by_key operations for inc/dec methods.
    * Added mget test to memslap.
    * Support for compatible ketama for SpyMemcached
    * Update C++ interface.