Merge branch 'search-results-filter-dropdown' into 'master'

Improved search results filter dropdown

## Current

Currently filter dropdowns on search results page can be **very** long and off the page

![Screen_Shot_2016-03-11_at_15.25.24](/uploads/3418b0a6f4f8a0a8bd2441b53502c574/Screen_Shot_2016-03-11_at_15.25.24.png)

## New

Changed over to the new dropdown

![Screen_Shot_2016-03-11_at_15.29.06](/uploads/2d3a4a9b3e50f3e0fc1748a026cd5905/Screen_Shot_2016-03-11_at_15.29.06.png)

See merge request !3183

app/assets/stylesheets/framework/dropdowns.scss

@@ -294,7 +294,7 @@
 }
 
 .dropdown-content {
-  max-height: 200px;
+  max-height: 215px;
   overflow-y: scroll;
 }
 

app/views/search/_filter.html.haml

@@ -6,13 +6,20 @@
     - else
       Any
     %b.caret
-  %ul.dropdown-menu
+  .dropdown-menu.dropdown-select.dropdown-menu-selectable
+    .dropdown-title
+      %span Filter results by group
+      %button.dropdown-title-button.dropdown-menu-close{aria: {label: "Close"}}
+        = icon('times')
+    .dropdown-content
+      %ul
         %li
-      = link_to search_filter_path(group_id: nil) do
+          = link_to search_filter_path(group_id: nil), class: ("is-active" if !params[:group_id].present?) do
             Any
+        %li.divider
         - current_user.authorized_groups.sort_by(&:name).each do |group|
           %li
-        = link_to search_filter_path(group_id: group.id, project_id: nil) do
+            = link_to search_filter_path(group_id: group.id, project_id: nil), class: ("is-active" if params[:group_id] == group.id.to_s) do
               = group.name
 
 .dropdown.inline.prepend-left-10.project-filter
@@ -23,11 +30,18 @@
     - else
       Any
     %b.caret
-  %ul.dropdown-menu
+  .dropdown-menu.dropdown-select.dropdown-menu-selectable
+    .dropdown-title
+      %span Filter results by project
+      %button.dropdown-title-button.dropdown-menu-close{aria: {label: "Close"}}
+        = icon('times')
+    .dropdown-content
+      %ul
         %li
-      = link_to search_filter_path(project_id: nil) do
+          = link_to search_filter_path(project_id: nil), class: ("is-active" if !params[:project_id].present?) do
             Any
+        %li.divider
         - current_user.authorized_projects.sort_by(&:name_with_namespace).each do |project|
           %li
-        = link_to search_filter_path(project_id: project.id, group_id: nil) do
+            = link_to search_filter_path(project_id: project.id, group_id: nil), class: ("is-active" if params[:project_id] == project.id.to_s) do
               = project.name_with_namespace