OAK-1667 - Encode Blob length as part of blobId in DataStoreBlobStore

Fix the test logic as we encode the length by default.

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1587802 13f79535-47bb-0310-9956-ffa450edef68
OAK-1726 - Improve support for local caching in DataStoreBlobStore

Adding CacheLIRS with default size of 16 MB. Any binary less than 17 KB can be cached

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1587803 13f79535-47bb-0310-9956-ffa450edef68