Add endpoint to get service date range for feed
Add error handling to service-dates endpoint
Fetch feed service dates in settings configuration
Fix InterstopDistance indicator and add test for ad-hoc system
Add comments about limits of InterstopDistance indicator
Merge pull request #281 from WorldBank-Transport/feature/stops-over-length-test

Fix InterstopDistance indicator and add test for ad-hoc system
Verify representative dates chosen are within feed serivce date range
Merge pull request #286 from flibbertigibbet/feature/check-date-range

Feature/check date range
Add weighted svc frequency indicator and new param method

Add weighted svc frequency test
Add param for multiple stops; weighted svc freq
Add tests for weighted svc freq