Add plus icon to all "Add X" buttons

app/views/profiles/keys/index.html.haml

@@ -3,7 +3,9 @@
 
 .gray-content-block.top-block
   .pull-right
-    = link_to "Add SSH Key", new_profile_key_path, class: "btn btn-new"
+    = link_to new_profile_key_path, class: "btn btn-new" do
+      = icon('plus')
+      Add SSH Key
   .oneline
     Before you can add an SSH key you need to
     = link_to "generate it.", help_page_path("ssh", "README")

app/views/projects/branches/index.html.haml

@@ -5,7 +5,7 @@
   .pull-right
     - if can? current_user, :push_code, @project
       = link_to new_namespace_project_branch_path(@project.namespace, @project), class: 'btn btn-create' do
-        %i.fa.fa-add-sign
+        = icon('plus')
         New branch
        
     .dropdown.inline

app/views/projects/labels/index.html.haml

@@ -4,6 +4,7 @@
 .gray-content-block.top-block
   - if can? current_user, :admin_label, @project
     = link_to new_namespace_project_label_path(@project.namespace, @project), class: "pull-right btn btn-new" do
+      = icon('plus')
       New label
   .oneline
     Labels can be applied to issues and merge requests.

app/views/projects/tags/index.html.haml

@@ -6,7 +6,7 @@
   - if can? current_user, :push_code, @project
     .pull-right
       = link_to new_namespace_project_tag_path(@project.namespace, @project), class: 'btn btn-create new-tag-btn' do
-        %i.fa.fa-add-sign
+        = icon('plus')
         New tag
   .oneline
     Tags give the ability to mark specific points in history as being important