Prevent initial ZK timeouts from killing the executor.

In addition, prevent uncaught exceptions from killing the executor.

Testing Done:
./pants src/test/python/apache/aurora/executor:executor-small
./src/test/sh/org/apache/aurora/e2e/test_end_to_end.sh

Bugs closed: AURORA-728

Reviewed at https://reviews.apache.org/r/25974/
Fixing unhandled error logging in updater

Bugs closed: AURORA-786

Reviewed at https://reviews.apache.org/r/26288/
Remove cron_policy related code.
Remove daemon bit.
Remove Twitter Specific links.
Remove health_check_interval_secs property.
Remove recipes.
Remove packer references.
Fix checkstyle issues.
Fix Import Order.