Flutile

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allow aadiff annotations

- `--caton82` for antigenic sites
- `--annotation-tables=STR` for list of annotation tables to load
- `--join-annotations` to join all annotations into one column

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* Fix bug in h3 trim
* Add tests for trim
* Add sequence samples from all h1 and h3 clades
* Add aadiff subcommand with absolute HA indexing against subtype refs

Add `trim`

Fix bug in --print-groups

Bug fixes

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Changes to represent:
* Add --print-groups option
* Add progress bar
* Only consider dates if --max-day-sep argument is given (no default)
* If --max-day-sep is given, keep the latest entry from each group, otherwise
keep first alphabetically
* Do not parse states unless --same-state is given