Migrate conversation in non-payment communities

- Remove old status
- Add new free status
Payment is now always enabled if status is accept
Improve migration
Merge pull request #511 from sharetribe/migrate-conversation-to-free

Migrate conversation to free
Cucumber feature for booking transaction process
Show per day in listing creation view
Submitting start on and end on to booking form
Pay per day
Added a bootstrap-datepicker for selecting booking days.
Data is not parsed on backend + some ToDos
changed dateformat to localization files
added overwrite rules/styles for vendor component: datepicker
adding price data to conversation after preauth payment
If booking, request expires when booking ends
Automatic confirmation after 1 day since the booking ended
refactored partial: _status.haml
Automatic confirmation footer
Remove duplicated migration from structure
Remove duplicate migration
Allow nil for price per
added some semicolons