Use Hadoop FileSystem abstraction for snapshotting

- closes #108
- Journal creation API redesign
- Supported by all journal except
  - MongoDB journal (coming soon)
  - InmemJournal
Upper replay limit and snapshotting for mongodb-casbah journal
Add more information about reliable channels
Use Java-port of LevelDB for all examples

- closes #110
Reliable channel : addition of comparison with Akka reliable proxy
Merge pull request #114 from cluelessjoe/master

Akka reliable proxy doc update
Reliable channel and remote destination guidelines

 - closes #113
It remains some Casbah reference.

Obviously, a bad copy and paste :-)
Merge pull request #116 from ndeverge/patch-1

It remains some Casbah reference.
Update journal docs

- do not use deprecated APIs
Reactive Journal upgrade to version 0.9-AKKA-2.2.0-RC1-SNAPSHOT

- Because ReactiveMongo has not upgraded to Akka 2.2.x yet we pulled and upgraded the source to Akka 2.2. These libraries are stored in Eligosource-snapshot repo until reactive is upgraded to Akka 2.2.x.
- The MongodbReactiveJournal now uses the ReactiveMongo 0.9 code base.
- Added 2 additional indexes to the ReactiveMongo journal for counter and replay.
- Added logging when a GetLastError encounters a failure.
- Changed connection.close to connection.askClose()
- Upgraded Embedded Mongo to current version for both the Reactive and Casbah journals.

Fixes #109