- Remove legacy processor, it probably was broken long time ago anyway
- Handle the case when `[airspace] boundary=` does not exist
- Handle the case when `[airspace] handoff=` does not exist
- Decouple common data sources from the directory tree
- Now common data sources can be specified in `[meta] common_data=`
- Values can be multi-line; each line will load another common data source
- Common data sources will be searched for similar to normal source files