ZEPPELIN-46 Allow modify Cron expression as well as select from preset.
Implementation based on select2
Merge branch 'master' into custom_cron_expr
ZEPPELIN-90 fix job overwritten bug
Remove debug print
Merge pull request #41 from NFLabs/custom_cron_expr

ZEPPELIN-46 Allow modify Cron expression as well as select from preset.
Merge pull request #44 from NFLabs/fix_job_overwrite_bug

ZEPPELIN-90 fix job overwritten bug