TBX: x.x, multiple texts TIGERSearch import module

Upgrade import module for TIGERSearch corpus.

see specifications: https://groupes.renater.fr/wiki/txm-info/public/import_tiger#version_2

(from redmine: issue id 2434, created on 2018/08/28 by Serge Heiden)

added import type::feature + 1 deleted label

changed milestone to %TXM Syntax 1.0

closed

assigned to @mdecorde