Tidy the logging plugin.

Change-Id: Id75901da628020c69c706ff0d8eee92ffdc7af61
Reviewed-on: http://gerrit.dmdirc.com/3845
Reviewed-by: Greg Holmes <greg@dmdirc.com>
Automatic-Compile: DMDirc Build Manager
Tidy various plugins.

In particular make the DNS plugin use the DNS dagger module, not
the debug module. Testing++.

Change-Id: If9dbd7303bdfda95f64553248e8e6175913dacd3
Reviewed-on: http://gerrit.dmdirc.com/3846
Reviewed-by: Greg Holmes <greg@dmdirc.com>
Automatic-Compile: DMDirc Build Manager