Bug 1064677 - Part 1: Default stumbler pref to 'off'. r=rnewman
Bug 1064677 - Part 2: Delay start of stumbler. r=rnewman

Removed starting stumbler from onResume(), broadcasting the stumbler startup
pref happens only in DelayedStartup. To further minimize the startup impact,
and so as not to compete for CPU/thread-space with more important services that
also have a delayed startup, delay by an additional second sending the start
message to stumbler.
Bug 1066101 - Use correct date for screen shot filename in Responsive Design View. r=jryans

The filename previously used the numeric day of the week instead of the day of
the month.