tv, iv and some of the undocumented tags are not converted

[alexeyev]

Alina Tillabaeva noticed that tags advl, equ, ger_ppot, mod_ind, prc_irre, prc_pcond, prc_plan (not described on apertium wiki) are not processed by the package.

Also, tags tv and iv (which ARE present in docs) are not converted to UT for some reason as well.