Combine entry masks by logical AND rather than replace

See merge request !21

Actually implement train removal for `--remove-trains SLICE_EXPRESSION`

See merge request !20

Actually remove sources when they should be removed

See merge request !18

Fix check for EXDF-v1.3 files masked as EXDF-v1.2 files

See merge request !17

Fix bugs from past refactoring that went unnoticed

See merge request !15

Fix get_index_root_data() to work with out-of-order trains in files

See merge request !16

Add lit frame selection

See merge request !14

Drop empty trains before reading in parallel with pasha

See merge request !13

Only touch sources when operations are properly handled

See merge request !12

Fix returning no mask when XTDF slicing is enabled but entire train selected

See merge request !11

Properly copy attributes of CONTROL key leafs and RUN-only keys

See merge request !9

Initial performance optimizations for frame selection pilots

See merge request !8

Add verbose profiling to debug logging

See merge request !7

Simplify reduction operation implementations and error handling

See merge request !6