added .woff2 and optimized svgs

_includes/header.html

@@ -2,7 +2,7 @@
     <div class="container navigation">
         <div class="navbar-header">
             <a href="{{ site.baseurl }}/">
-                <img src="/img/hip_logo.svg" class="logo" alt="{{ site.title }}">
+                <img src="/img/hip_logo_opt.svg" class="logo" alt="{{ site.title }}">
             </a>
             <button type="button" class="navbar-toggle collapsed" data-toggle="collapse"
                     data-target=".navbar-collapse">