Remove fontello

This is no longer used now that the octicons include video/audio
on/off icons that are used in the collaboration package.

static/fontello-mixins.less

@@ -1,20 +0,0 @@
-@fontello-video: "\e800";
-@fontello-audio: "\e801";
-
-.fontello-icon(@name, @size: 16px) {
-  &:before {
-    font-family: 'fontello';
-    font-weight: normal;
-    font-style: normal;
-    display: inline-block;
-    line-height: 1;
-    -webkit-font-smoothing: antialiased;
-    text-decoration: none;
-
-    font-size: @size;
-    width: @size;
-    height: @size;
-
-    content: @@name
-  }
-}

static/root-view.less

@@ -69,10 +69,3 @@ html, body {
     min-width: 0;
   }
 }
-
-@font-face {
-  font-family: 'fontello';
-  src: url("fontello.woff") format("woff");
-  font-weight: normal;
-  font-style: normal;
-}