UI -- Repalce "Commerials" with "Materials".

This only replaces the UI facing wording. Specs will fail
as they have not been updated yet.

app/views/admin/events/index.html.haml

@@ -6,9 +6,9 @@
         = "(#{@events.length})" if @events.any?
 
         .btn-group.pull-right
-          %button.btn.btn-primary{ title: 'Mass import of commercials for events',
+          %button.btn.btn-primary{ title: 'Mass import of materials for events',
             data: { toggle: 'modal', target: '#mass-commercials-modal' } }
-            Add Commercials
+            Add Materials
 
           - if can? :create, Event
             = link_to 'Add Event',
@@ -28,7 +28,7 @@
   .modal-dialog
     .modal-content
       .modal-header
-        %h1 Add commercials to events
+        %h1 Add materials to events
         .text-muted
           Upload your file with data in the following format:
           %b Event_ID:Commercial_Link

app/views/admin/events/show.html.haml

@@ -11,7 +11,7 @@
           - progress_status = @event.progress_status
           = progress_status.reject{ |_key, value| value || value.nil? }.length
     %li
-      = link_to 'Commercials', '#proposal-commercials', 'data-toggle' => 'tab'
+      = link_to 'Materials', '#proposal-commercials', 'data-toggle' => 'tab'
 
   .tab-content
     #proposal-content.tab-pane.active