fix up downloadApk cookie jar
add download file example
unref cache timer

- closes #2 using timer unref, see
  http://nodejs.org/api/timers.html#timers_unref
formatting nit
remove cruft test code
set debug to false by default in downloadInfo
Merge branch 'dev'

* dev:
  set debug to false by default in downloadInfo
  remove cruft test code
  formatting nit
  unref cache timer
  add download file example
  fix up downloadApk cookie jar