Ports the Chem Master choose your pill PR plus post-improvements

tgui/tgui.html

@@ -16,7 +16,8 @@
       };
     </script>
     <link rel='stylesheet' href='tgui.css'/>
-    <link rel='stylesheet' href='spritesheet_pipes.css'/>
+    <!-- This is processed in byond, so interfaces can override the html head if needed, for custom sheets of style etc -->
+    <!--customheadhtml-->
     <script id='data' type='application/json' data-ref='[ref]'>{}</script>
     <script defer src='tgui.js'></script>
   </head>