Revert "Revert "PCBC-227: Allow store of pure numeric keys""

This reverts commit afe52004e33d9f1ec4e903ea77a2d6bcf03bc096.

Change-Id: Id5aab9c0b4a7009fd9b89fabe772bd903b863259
Reviewed-on: http://review.couchbase.org/29201
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>