Removed advertisement variables

<ul>
    <li>Removed advertisement variables</li>
    <li>Changed <code>selectTab("modpacks");</code> to <code>selectTab(TAB_MODPACKS);</code> incase <code>TAB_MODPACKS</code> is changed</li>
    <li>Shortened some if statements. (I would of done some more, but I wasn't sure if they were going to be expanded)</li>
</ul>