Added a migrate method to the ServiceController so that the WindowsServiceController can migrate the old registry entry value.  Changed ServiceControllerFactory to use SystemUtils.
Issue: MIRTH-1857
MIRTH-2716: Added a migrateMetaData method to ImportConverter3_0_0. All it needs to do is remove the "mule-properties" node from connector metadata.
MIRTH-2717: Fixed issue that caused a single invalid channel in the database to bring the whole server down. This can happen anytime the serialized XML in the database references something that is no longer on the classpath (e.g. an extension that hasn't been loaded on first upgrade, etc.). Before it was only catching and logging SQLException, but now we're doing the same for LinkageError. If it encounters an object that it can't deserialize, it will just send an entry to the server log and move on.
Fixed deadlock problems with the Data Pruner when running SQL Server.

Updated the data pruner statements for SQL Server so that it is forced to use the "pruneMessagesByIds" mode and so that it does not rely on cascade deletion. This resolves a contention issue between the pruner and message processing.
Issue: MIRTH-2689
Updated README.txt for 3.0.0.
Issue: MIRTH-1713
Appended license headers
Organized imports