minor, migrate tf(1) as was to an umbrella tool, commands add, get, and list

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, provide iterators for corpora (only the terms for now)

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
chore, provide convenience macro if_with

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, use corpus iterators to list all terms in a corpus file

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, kill corpus argument from unnamed args, use --corpus|-f again

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'feat/tf-umbrella'

* feat/tf-umbrella:
  minor, kill corpus argument from unnamed args, use --corpus|-f again
  minor, use corpus iterators to list all terms in a corpus file
  chore, provide convenience macro if_with
  minor, provide iterators for corpora (only the terms for now)
  minor, migrate tf(1) as was to an umbrella tool, commands add, get, and list
minor, provide frequency iterators and corpus_get_freqs() convenience fun based on them

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, provide secret idf command

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, overload the list command with idf output

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
fix, PEBKAC, free the corpus object after use in list command

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, introduce document counting via corpus_{get,add}_ndoc()

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
fix, PEBKAC, document term freqs are always >0 ...

or else they wouldn't be stored in the corpus.

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, implement idf properly

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
major, kill idf(1) tool again, its functionality is merged into tf(1)

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'feat/tf-idf-merge'

* feat/tf-idf-merge:
  major, kill idf(1) tool again, its functionality is merged into tf(1)
  minor, implement idf properly
  fix, PEBKAC, document term freqs are always >0 ...
  minor, introduce document counting via corpus_{get,add}_ndoc()
  fix, PEBKAC, free the corpus object after use in list command
  minor, overload the list command with idf output
  minor, provide secret idf command
  minor, provide frequency iterators and corpus_get_freqs() convenience fun based on them