Use dedicated classes for transport properties and configs.

api/net/sf/briar/api/TransportConfig.java

api/net/sf/briar/api/TransportProperties.java

api/net/sf/briar/api/db/DatabaseComponent.java

api/net/sf/briar/api/plugins/TransportPlugin.java

api/net/sf/briar/api/protocol/TransportUpdate.java

api/net/sf/briar/api/protocol/writers/TransportWriter.java

api/net/sf/briar/api/transport/TransportCallback.java

components/net/sf/briar/db/Database.java

components/net/sf/briar/db/DatabaseComponentImpl.java

components/net/sf/briar/db/JdbcDatabase.java

components/net/sf/briar/invitation/InvitationWorker.java

components/net/sf/briar/plugins/AbstractPlugin.java

...nents/net/sf/briar/plugins/bluetooth/BluetoothPlugin.java

...s/net/sf/briar/plugins/file/RemovableDriveFinderImpl.java

...nents/net/sf/briar/plugins/file/RemovableDrivePlugin.java

...nents/net/sf/briar/plugins/socket/SimpleSocketPlugin.java

components/net/sf/briar/plugins/socket/SocketPlugin.java

components/net/sf/briar/protocol/TransportFactory.java

components/net/sf/briar/protocol/TransportFactoryImpl.java

components/net/sf/briar/protocol/TransportReader.java