Reactive Mongo Initial Commit

- Cleaned up casbah readme.
- Setup reactive mongo journal.
- Modifed Build.scala to support reactive mongo IT tests.

Pull request modifications from comments

- Updated readme.md to reflect reactive mongo.
- Modified Reactive Journal to manage mongo connection.
- Modified Reactive Journal Properties to accect mongo connection
configuration variables.
- Updated test fixtures and support specs to support journal's
management of mongo connection.
- #83 ReactiveMongo Journal

Address unique index sequence number for reactive mongo

- Updated ReliableChannelSpec to set sequenceNr.
- Updated MongodbReactiveJournal to use insert to return future.
- #83 ReactiveMongo Journal
Merge pull request #86 from eligosource/wip-83-ddevore-mongodb-reactive

Reactive Mongo Initial Commit - squashed commits
- #83 complete
Fix erroneous link in user guide (FSM).
Merge pull request #88 from ahjohannessen/fsm-link-fix

Fix erroneous link in user guide (FSM).
typo (repeated)
Merge pull request #91 from etaty/patch-1

typo (repeated)
Snapshot support (closes #8)

- for LevelDB journal
- for In-memory journal

Further tickets closed:

- Throttled replay support discontinued (closes #87)
- Upper replay limit (closes #89)
- Set processor id before writing messages (closes #90)

Further changes and additions:

- new replay API (ReplayParams)
- Refactor SynchronousWriteReplaySupport
- Refactor AsynchronousWriteReplaySupport
- Rename SnapshottedReplay to IsolatedReplay
- Replay specification
- User guide updated
Move google-protobuf depedency

- from eventsourced-core
- to eventsourced-journal-common
Merge pull request #93 from eligosource/wip-8-snapshots

Snapshot support (closes #8)
Standalone channel usage (closes #84)

- Channel accepts event messages with processor id 0
- Channel accepts plain events
- Standalone channel usage example
- Fix erroneous sequence number recovery with Journal.IO (closes #95)
- Reset temporary sender paths for previously persisted output messages
- Undo temporary changes in ReliableChannelSpec
- Additional tests
  * sequence number recovery
  * sender path reset
Merge pull request #96 from eligosource/wip-84-standalone-channels

Standalone channel usage (closes #84)
Enforce positive processor and channel ids

- closes #47
User guide extension

- refer to channel by id when creating an emitter
Snapshotting for Journal.IO journal (closes #97)

- incl. support for upper replay limit
- refactorings
  * packages util and serialization for journal-commons
  * generalize snapshot storage on local filesystem
Update snapshot section in user guide

- to reflect snapshotting support of Journal.IO journal
Merge pull request #99 from eligosource/wip-97-snapshotting-journalio

Snapshotting for Journal.IO journal (closes #97)
Provide snapshot metadata for deserialization
Snapshot object creation moved to framework

- deserializeSnapshot only needs to return state
Snapshotting for HBase journal (closes #98)

- common snapshotting functionality in AsynchronousWriteReplaySupport
- Hadoop FileSystem based snapshot storage
- Fix erroneous non-isolated counter value writes (closes #74)
- Drop useless writer actors (in AWRS)
  - some async database clients will anyway support concurrent writes
  - in all other cases, concurrent writes should be a backend-specific implementation
- extended replay tests
Merge pull request #100 from eligosource/wip-98-snapshots-hbase

Snapshotting for HBase journal (closes #98)