Switch from compounds model system to Bookshelf

Uses JSON schemas with tv4 for validation
Improve relation between controller and model
Move all fields to JSON schema
Remove more legacy stuff
Factor out Loan Collection definition
Get authentication straight
Introduce ADMIN_PARTY mode, serve static

This allows SYNDiCAT to run standalone
Update README.md with setup instructions.
Hint for non-Debian nodejs
Fix bookshelf version
Upgrade Bookshelf dependency
Adapt tests to new bookshelf version
Fix contract state updating
Make rate of interest mandatory
Introduce Loan::toCompoundViewObject method
Add interest_yearly_to field to schema
Do not fail on optional fields with null as value
Improve put_state test
Fix contract rendering
Merge pull request #4 from codelila/bookshelf

Switch to bookshelf