Add support for multilingual hashtags (cr0bar)

refactor: move hashtag tests to their own file (William Casarin)

Added non-latin test and amended emoji test to include emoji in hashtag (cr0bar)

Handle percent encoding of colon for some hashtags (cr0bar)

Change to is_hashtag_chat to support non-latin characters (cr0bar)

Fix to is_boundary to support non-latin characters (cr0bar)

git: add .mailmap file (William Casarin)

fix project issues (William Casarin)

pushed to refs/heads/master