Retire semantic_form_for

Also a buttload of form cleanups...

app/views/admin/users/_form.html.haml

@@ -1,26 +0,0 @@
-= semantic_form_for [:admin, @user] do |f|
-  = f.inputs 'Basic Information' do
-    - unless @user.new_record?
-      .pull-right
-        %b
-          Confirmed?
-        - if can? :toggle_confirmation, @user
-          = check_box_tag @user.id, @user.id, @user.confirmed?,
-            url: "#{toggle_confirmation_admin_user_path(@user.id)}?user[to_confirm]=",
-            class: 'switch-checkbox',
-            readonly: false
-        - else
-          = check_box_tag @user.id, @user.id, @user.confirmed?,
-            url: "#{toggle_confirmation_admin_user_path(@user.id)}?user[to_confirm]=",
-            class: 'switch-checkbox',
-            readonly: true
-    = f.input :is_admin, hint: 'An admin can create a new conference, manage users and make other users admins.'
-    = f.input :name, as: :string
-    = f.input :username, :as => :string if @user.new_record?
-    = f.input :email
-    = f.input :password if @user.new_record?
-    = f.input :affiliation, as: :string
-    = f.input :biography, input_html: { rows: 10, data: { provide: 'markdown' } },
-      hint: markdown_hint
-  = f.actions do
-    = f.action :submit, button_html: {class: 'btn btn-primary'}