Log the exception class when logging exceptions.

api/net/sf/briar/api/serial/SigningConsumer.java

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

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

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

components/net/sf/briar/i18n/FontManagerImpl.java

components/net/sf/briar/i18n/I18nImpl.java

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

...ts/net/sf/briar/lifecycle/WindowsShutdownManagerImpl.java

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

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

...briar/plugins/bluetooth/BluetoothTransportConnection.java

...ts/net/sf/briar/plugins/bluetooth/ConnectionCallback.java

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

...ts/net/sf/briar/plugins/bluetooth/InvitationListener.java

components/net/sf/briar/plugins/file/FilePlugin.java

...onents/net/sf/briar/plugins/file/FileTransportReader.java

...onents/net/sf/briar/plugins/file/FileTransportWriter.java

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

...et/sf/briar/plugins/file/WindowsRemovableDriveFinder.java

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