Added deprecation note on usage docs

docs/usage.html

@@ -48,6 +48,8 @@ <h2>Table of Contents</h2>
 	</ol>
 	</div>
 	<hr>
+	<p class="faint"><b>Note</b>: Some screenshots may be outdated, but even if that's the case they should convey the point well enough to still be relevant. If something major changes, they get replaced.</p>
+	<hr>
 <!------------------------------------------------------------------->
 	<h2>Building &amp; Running</h2>
 	<div class="h-indent">