disable automatic thumbnail generation
update MetadataCommunity identifier
fix some pep8 problems in db_upgrader.py
skip metadata test
clean up thumbnails
fix typo
Merge pull request #981 from LipuFei/disable_thumbnails

Disable automatic thumbnail generation
Lower log level for tunnel most of the tunnel community.
Merge pull request #988 from whirm/lower_tunnel_loglevels

Lower log level for tunnel most of the tunnel community.