Move tree-related views from refs to trees

app/views/tree/_head.html.haml

+%ul.nav.nav-tabs
+  %li
+    = render partial: 'shared/ref_switcher', locals: {destination: 'tree', path: params[:path]}
+  %li{class: "#{'active' if (controller.controller_name == "refs") }"}
+    = link_to tree_project_ref_path(@project, @ref) do
+      Source
+  %li.right
+    .input-prepend.project_clone_holder
+      %button{class: "btn small active", :"data-clone" => @project.ssh_url_to_repo} SSH
+      %button{class: "btn small", :"data-clone" => @project.http_url_to_repo} HTTP
+      = text_field_tag :project_clone, @project.url_to_repo, class: "one_click_select span5"