Add UNINITIALIZED state and show help tab if HQ comm error on start up.

re: ArchiveTeam/seesaw-kit#20
warrior: Add contacting HQ fail concern and show msg in warrior UI.
Merge branch 'issue/20-hq-error' into development

Closes ArchiveTeam/seesaw-kit#20
warrior: Limit item output to last 500 lines.

Closes ArchiveTeam/seesaw-kit#75
tracker.py: Friendlier error messages.
tracker.py: Set tracker retry delay to 60s and increment up to 300s.

Closes ArchiveTeam/seesaw-kit#74
Merge branch 'development'
Release version 0.7