Add text transliteration output

[reynoldsnlp]

https://en.wikipedia.org/wiki/Romanization_of_Russian#Transliteration_table

The idea would be that code something like the following would work:

t = Text('Слова на научную тему.')
t.transliterate()  # scholarly is the default
# 'Slova na naučnuju temu.'
t.transliterate('iso9')
# 'Slova na naučnuû temu.'

[reynoldsnlp]

resolved in b34532e