DATAREDIS-562 - Polishing.

Move BitfieldCommand to top-level type BitFieldSubCommands.
Use primitives in command objects. Add toString methods. Add utility methods to extract responses from Jedis Client. Use Connection.execute(…) to invoke BITFIELD using Jedis. Fix Overflow values to string rendering.
Convert test ticket references to new format.

Original pull request: #227.

Author: mp911de

src/main/asciidoc/new-features.adoc

@@ -12,6 +12,7 @@ New and noteworthy in the latest releases.
 * `@TypeAlias` Support for Redis repositories.
 * Cluster-wide `SCAN` using Lettuce and `SCAN` execution on a selected node supported by both drivers.
 * <<redis:reactive:pubsub,Reactive Pub/Sub>> to send and receive a message stream.
+* `BITFIELD`, `BITPOS`, and `OBJECT` command support.
 
 [[new-in-2.0.0]]
 == New in Spring Data Redis 2.0