Updated everything to version 3.1.0.

Added migrate3_1_0 method to the Migratable interface, and also to all implementations.

Added call to migrate3_1_0 in MigratableConverter.

Added V3_1_0 to the Version enum.

Added 3.1.0 to the switch statement in ServerMigrator.

Updated all creation SQL scripts to insert version 3.1.0.

Updated mirth-build.properties to pass in 3.1.0.

Updated all plugin/connector metadata files to use 3.1.0 for the mirthVersion
Issue: MIRTH-3325
MIRTH-3278: Requests are no longer sent to the server when there are no channels or connectors affected.
MIRTH-3329: Fixed bug that caused connector type decorations to be applied to the destination table even if the source tab is currently selected.