Add empty keyphrases check, logging for spaCy pipeline download and parameter types

v0.0.3

Merge remote-tracking branch 'origin/master'

Update project description

update project description

Signed-off-by: Tim Schopf <tim.schopf@t-online.de>

Initial KeyphraseVectorizers release

The initial release contains KeyphraseCountVectorizer and KeyphraseTfidfVectorizer classes.