format is type and type is event,raster, etc

We included format in the backend in https://github.com/nens/lizard-nxt/pull/542/files and used type to describe a functional data type. This enables us to query data on type (events). 

Actions
- [x] Refactor type to format.
- [x] Check for options.type in getData and act accordingly.
- [ ] Rewrite the way timeline gets data to use options.type as a filter.