First implemenation of <mouse> in rc.xml

First implemenation of <mouse> in rc.xml

Can successfully parse the following XML and and implement the action:

<mouse>
    <context name="TitleBar">
        <mousebind button="Left" action="DoubleClick">
            <action name="ToggleMaximize"/>
        </mousebind>
    </context>
</mouse>

The XML parsing code for this looks A LOT different than the already
existing XML parsing code. It may have to be reworked