Mark billed entries in the timeline (closes: #239c27)

stoptime.rb

@@ -1234,7 +1234,7 @@ module StopTime::Views
         end
       end
       @time_entries.each do |entry|
-        tr do
+        tr(:class => entry.task.billed? ? "billed" : nil) do
           td { a entry.task.name,
                  :href => R(CustomersNTasksN, entry.customer.id, entry.task.id) }
           td { a entry.date.to_date,

templates/sass/style.sass

@@ -17,6 +17,9 @@ $dark-red: #990000
   clear: both
   padding-top: 10px
 
+.billed
+  text-decoration: line-through
+
 /* Basic elements */
 a
   text-decoration: none