Add an empty upgrade command
Add data store version discovery helpers
Declare KVStore as map directly for simplicity (json decoding)
Add upgrade command supporting 0.3 to >0.3 version migration
Update the updgrade functions to be more version specific
Write a backup of the data store being upgraded
Add a --no-backup option if users don't want to backup old store when upgrading
Autodetect base store version on upgrade
Enhance version upgrade logging
Add interactive upgrade + --yes flag support
gofmt