Draft: Enhancement/improve ecmwf crawler
- The ECMWF data crawler now downloads a fallback variable in case the desired ECMWF ERA dataset does not cover the requested time interval. This allows to download ECMWF data for dates before 6/2012.
- Added some bug fixes, comments and improved code style in the ECMWF module.
- Added additional ERA interim setups for T2M, O3, and SLP.
- Reordered ERA setups.
- Unavailable ECMWF variables are now automatically skipped.
- Added ECMWF crawler tests.
Fixes issue #75.
Edited by Daniel Scheffler