[accessibility] add hidden labels for input fields

app/views/cost_objects/_labor_budget_item.rhtml

@@ -15,12 +15,15 @@
 <% fields_for prefix, labor_budget_item do |cost_form| %>
 <tr class="cost_entry <%= classes %>" id="<%= id_prefix %>">
   <td class="units">
+    <label class="hidden-for-sighted" for="<%= id_prefix %>_units"><%= l(:field_hours) %></label>
     <%= cost_form.text_field :hours, :index => id_or_index, :size => 3 %>
   </td>
   <td class="user">
+    <label class="hidden-for-sighted" for="<%= id_prefix %>_user_id"><%= l(:label_user) %></label>
     <%= cost_form.select :user_id, @project.assignable_users.sort.collect{|u| [u.name, u.id]}, {:prompt => true}, {:index => id_or_index} %>
   </td>
   <td class="comment">
+    <label class="hidden-for-sighted" for="<%= id_prefix %>_comments"><%= l(:field_comments) %></label>
     <%= cost_form.text_field :comments, :index => id_or_index, :size => 40 %>
   </td>
   <td class="currency">

app/views/cost_objects/_material_budget_item.rhtml

@@ -15,17 +15,20 @@
 <% fields_for prefix, material_budget_item do |cost_form| %>
 <tr class="cost_entry <%= classes %>" id="<%= id_prefix %>">
   <td class="units">
+    <label class="hidden-for-sighted" for="<%= id_prefix %>_units"><%= l(:field_units) %></label>
     <%= cost_form.text_field :units, :index => id_or_index, :size => 3 %>
     <span id="<%= "#{id_prefix}_unit_name" %>">
       <%=h material_budget_item.cost_type.unit_plural if material_budget_item.cost_type %>
     </span>
   </td>
   <td class="cost_type">
+    <label class="hidden-for-sighted" for="<%= id_prefix %>_cost_type_id"><%= l(:field_cost_type) %></label>
     <%= cost_form.select :cost_type_id, cost_types_collection_for_select_options(material_budget_item.cost_type), {}, {:index => id_or_index} %>
     <%= observe_field( "#{id_prefix}_cost_type_id", :url => {:action => :update_material_budget_item, :project_id => @project.id}, :with => "'cost_type_id=' + encodeURIComponent(value) + '&units=' + encodeURIComponent(document.getElementById('#{id_prefix}_units').value) + '&fixed_date=' + encodeURIComponent(document.getElementById('cost_object_fixed_date').value) + '&element_id=#{id_prefix}'") %>
     <%= observe_field( "#{id_prefix}_units", :frequency => 1, :url => {:action => :update_material_budget_item, :project_id => @project.id}, :with => "'cost_type_id=' + encodeURIComponent(document.getElementById('#{id_prefix}_cost_type_id').value) + '&units=' + encodeURIComponent(value) + '&fixed_date=' + encodeURIComponent(document.getElementById('cost_object_fixed_date').value) + '&element_id=#{id_prefix}'") %>
   </td>
   <td class="comment">
+    <label class="hidden-for-sighted" for="<%= id_prefix %>_comments"><%= l(:field_comments) %></label>
     <%= cost_form.text_field :comments, :index => id_or_index, :size => 40 %>
   </td>
   <td class="currency">