Removed 'version' field from the Connector class, since it is no longer used.
Issue: MIRTH-2732
MIRTH-2753: Fixed bug that caused the version attribute to not be exported for invalid channels.
MIRTH-2755: Added ability for the client to alert users when an invalid channel doesn't have one or more required plugins currently loaded.
Remove version column when migrating connectors to 3.0.0.
Issue: MIRTH-2732
Removed unused migrateMetaDataId field in the Connector class.
Issue: MIRTH-2552
MIRTH-2295: Fixed ArrayIndexOutOfBoundsException occurring in the web service connector service. The client now also calls alertException rather than alertError to show more detailed information.
Synchronized deploy, undeploy, and redeployAll methods on the server.  Also synchronized setServerConfiguration with these methods so that none of these tasks can be performed at the same time.

Removed unused deployChannel and undeployChannel methods from the EngineController API.

Also fixed a bug where ChannelPlugin deploy and undeploy hooks were not all getting called.

These changes should also fix MIRTH-2756.
Issue: MIRTH-2693
After a connector is halted, it now dispatches an idle state event. For the most part, this will cause connectors to be in the IDLE state after being halted. 

However, in rare circumstances depending on the connector, it is possible for the connector to still be in a different state. This is determined by the connector's implementation.
Issue: MIRTH-2686