birdnotes.py: Objects to represent bird note files

For a discussion of the phrase structure used to represent arbitrary text, see Section 19, “class Paragraph: One paragraph of mixed text”.

# - - -   P a r a g r a p h . a d d P h r a s e

    def addPhrase(self, tag, text):
        """Add one phrase to self._phraseList.
        """
        self._phraseList.append((tag, text))