* glib/Log.cs: Make LogLevelFlags CLS compliant.
* glib/SignalCallback.cs: Set the constructor protection level to
protected, since it can not be instantiate.d
* glib/Marshaller.cs: Do not allow instances of this class as it
only exposes static methods.
* glib/Source.cs, glib/FileUtils.cs, glib/Timeout.cs,
glib/Thread.cs, glib/Markup.cs, glib/TypeConverter.cs: Ditto.
svn path=/trunk/gtk-sharp/; revision=20573