add alternative output formats

[reynoldsnlp]

This may not be possible in every case, but where possible, add other common output formats:

• connl(x/u)
• mystem
• Multext-East (Sharoff, et al.)
• etc?

[reynoldsnlp]

As for connl-u format, there does not appear to be any way to represent ambiguity, so the conversion would be lossy.

[reynoldsnlp]

mystem can have ambiguous readings separated by | in its output, even with the -d (disambiguate) flag:

$ echo "Мы уже работаем здесь три недели." | mystem3.1 -ind
Мы{мы=SPRO,мн,1-л=им}
уже{уже=ADV=}
работаем{работать=V,несов,нп=непрош,мн,изъяв,1-л}
здесь{здесь=ADVPRO=}
три{три=NUM=им|три=NUM=вин,неод}
недели{неделя=S,жен,неод=вин,мн|неделя=S,жен,неод=род,ед|неделя=S,жен,неод=им,мн}