v0.4.0

Added velvoitetarkastus functionality
Consists of three database functions

• update_velvoitteet()
• velvoite_status()
• tallenna_velvoite_status()

Improved kohde updating

• Retroactively pass relevant information from expiring kohde to a new kohde, when applicable.
• More accurate expiration and creation dates.

Full Changelog: v0.3.0...v0.4.0