Update to GAE SDK 1.8.8

Signed-off-by: Greg Meiste <greg.meiste@gmail.com>
Configuration: Enable threadsafe - Closes #14

Signed-off-by: Greg Meiste <greg.meiste@gmail.com>
Add cron for device cleanup (dry run only for now). Phase 2 of #11

Signed-off-by: Greg Meiste <greg.meiste@gmail.com>
Store user ID with device ID if available

If user ID is not available, do not set/update the userId
property.

Signed-off-by: Greg Meiste <greg.meiste@gmail.com>
Remove schema update for devices. No longer needed.

Signed-off-by: Greg Meiste <greg.meiste@gmail.com>
Deploy version 31 to GAE

Signed-off-by: Greg Meiste <greg.meiste@gmail.com>