Replace files icons with fontawesome

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/assets/stylesheets/sections/tree.scss

@@ -57,6 +57,10 @@
         }
       }
 
+      i {
+        color: $bg_primary;
+      }
+
       img {
         position: relative;
         top:-1px;

app/helpers/tree_helper.rb

@@ -25,8 +25,13 @@ module TreeHelper
   #
   # type - String type of the tree item; either 'folder' or 'file'
   def tree_icon(type)
-    image = type == 'folder' ? 'file_dir.png' : 'file_txt.png'
-    image_tag(image, size: '16x16')
+    icon_class = if type == 'folder'
+                   'icon-folder-close'
+                 else
+                   'icon-file-alt'
+                 end
+
+    content_tag :i, nil, class: icon_class
   end
 
   def tree_hex_class(content)

app/views/projects/tree/_submodule_item.html.haml

 - tree, commit = submodule_links(submodule_item)
 %tr{ class: "tree-item" }
   %td.tree-item-file-name
-    = image_tag "submodule.png"
+    %i.icon-archive
     %span
       = link_to truncate(submodule_item.name, length: 40), tree
     @

app/views/projects/tree/_tree.html.haml

@@ -36,8 +36,7 @@
     - if @path.present?
       %tr.tree-item
         %td.tree-item-file-name
-          = image_tag "file_empty.png", size: '16x16'
-          = link_to "..", project_tree_path(@project, up_dir_path(tree))
+          = link_to "..", project_tree_path(@project, up_dir_path(tree)), class: 'prepend-left-10'
         %td
         %td
         %td