</b> supports three optional named parameters: Type,
Name and Description. Name and Description are strings representing the name
of the extension and a description of what it does. If no name is provided,
the name of the class is used. Type may be any one or a combination of the
ExtensionType enum members:

<pre class="prettyprint">
	[Flags]
	public enum ExtensionType
	{
		Core=1,
		Client=2,
		Gui=4
	}
</pre>

The values may be or'ed together, allowing for future Addins that require
extensions at multiple