work towards make test_public_headers_build pass
- add missing include rules needed by headers that aren't compiled regularly within a package (including dependencies on public_headers that aren't tracked by cmake)
- Associators/AssociatorsBase
- Event/DigiEvent
- Event/TrackEvent
- Kernel/LHCbKernel
- add missing include statements to headers that were usually fulfiled by implementation files
- Day/MDF
- Det/DetDesc
- Kernel/SOAExtensions
- Kernel/LHCbKernel
Edited by Paul Seyfert