TAF bulletin serialisation
- Added support for converting TAF bulletin Java object into Strings following the GTS Meteorological Bulletin syntax (WMO-No.386, ed. 2015)
- Adopted to changes in the fmi-avi-messageconverter release 3.0.0:
- Missing observed cloud layer info better handled for METARs
- Fixed a bug of not populating prevailing visibility when directional visibility was given as 'NDV' in TAC