Merge branch 'header-mobile-overflow' into 'master'

Fixes issue with signin button overflowing on mobile

Closes #14477

![Screen_Shot_2016-03-22_at_13.52.51](/uploads/7c9b2c38be7d497c690a7d17ae0ca76d/Screen_Shot_2016-03-22_at_13.52.51.png)

![Screen_Shot_2016-03-22_at_13.52.43](/uploads/8b2432aeb4afec455286fced11c5490c/Screen_Shot_2016-03-22_at_13.52.43.png)

See merge request !3342

app/assets/stylesheets/framework/common.scss

@@ -292,8 +292,11 @@ table {
 }
 
 .btn-sign-in {
-  margin-top: 10px;
   text-shadow: none;
+
+  @media (min-width: $screen-sm-min) {
+    margin-top: 11px;
+  }
 }
 
 .side-filters {

app/assets/stylesheets/framework/header.scss

@@ -70,6 +70,11 @@ header {
 
   .header-content {
     height: $header-height;
+    padding-right: 20px;
+
+    @media (min-width: $screen-sm-min) {
+      padding-right: 0;
+    }
 
     .title {
       margin: 0;

app/views/layouts/header/_default.html.haml

@@ -6,7 +6,7 @@
         = icon('bars')
 
       .navbar-collapse.collapse
-        %ul.nav.navbar-nav.pull-right
+        %ul.nav.navbar-nav
           %li.hidden-sm.hidden-xs
             = render 'layouts/search'
           %li.visible-sm.visible-xs
@@ -38,7 +38,8 @@
               = link_to destroy_user_session_path, class: 'logout', method: :delete, title: 'Sign out', data: {toggle: 'tooltip', placement: 'bottom', container: 'body'} do
                 = icon('sign-out')
           - else
-            .pull-right
+            %li
+              %div
                 = link_to "Sign in", new_session_path(:user, redirect_to_referer: 'yes'), class: 'btn btn-sign-in btn-success'