Adds IFU support
Adds features required for IFU integration or developed during the integration:
- Adds support for IFU files in
gris_translate_headers
- Adds
IFUFitsFile
subcalss to GrisFitsfile - Adds WCS generator for IFU data
- Added
gris_parse_calib
script to retrieve reduction settings from IDL scripts - Switched WCS generation to structure using ABCs with more structured interface
- Removed too specific test for coordinates