Set up consistent API for resources, organisations, and persons
Improve error handling and logging
Fix issue with organisation title queries
Basic setup for an endpoint that searches all entities

Call individual, specialized endpoints internally and compose
results in a JSON map, using the individual endpoint names as keys.
Replace old endpoints with new API, update documentation and tests
Add comment and test for resource-by-subject sample request
Merge pull request #53 from fsteeg/api

New API and documentation with sample requests