Added support for RefReplicated and RefReplicationDone events

Defined DTO objects for both events. These events allow to know when
the replication of a ref is completed to a specific node and to all
the nodes.

Change-Id: I6d25b21abcadc078ce9845756e39ab4235caddfa
Remove duplicated implements GerritJsonEvent

All events extends GerritTriggeredEvent which implements GerritJsonEvent,
no need for event to implements the same interface.

Change-Id: I8b866110108f8661a61c3fbf3bc166fbf454bfea
Use documentation from frontend as help

Get frontend url from configuration and use it for displaying
search help.
Merge pull request #113 from hugares/replicationevents

Added support for RefReplicated and RefReplicationDone events
Fixed @link annotation in javadoc.

Add missing space after @link annotation in the RefReplicatedTest and
RefReplicationDoneTest.

Change-Id: I0c078175b9e114ccc2ed2e93c85eba2c434f6c44
Merge pull request #114 from jyrkiput/jelly-help

Use documentation from frontend as help
Merge pull request #115 from hugares/interfacecleanup

Remove duplicated implements GerritJsonEvent
Merge pull request #116 from hugares/fixjavadoc

Fixed @link annotation in javadoc.