Port navbar changes to eex layout

web/static/css/base.sass

@@ -5,7 +5,6 @@ body
   font-family: "Source Sans Pro", "Helvetica Neue", Helvetica, Arial, sans-serif
   font-size: 15px
   background-color: $background-color
-  padding-top: 42px
 
   &.modal-open
     margin-right: 0

web/templates/layout/header.html.eex

@@ -1,4 +1,4 @@
-<header class="navbar navbar-default navbar-fixed-top" role="navigation">
+<header class="navbar navbar-default" role="navigation">
   <div class="container">
     <div class="navbar-header">
       <button class="navbar-toggle" data-target=".navbar-ex1-collapse" data-toggle="collapse" type="button">