The Group Line wizard should be programmatically useable

The Group Line wizard provides a useful functionality that people will want to reuse withour resorting to create a session, etc.

assigned to @nicoe

added accounting type::feature + 1 deleted label

review268331003 updated at https://codereview.tryton.org/268331003/#ps268341002

added 1 deleted label and removed 1 deleted label

review268331003 updated at https://codereview.tryton.org/268331003/#ps288401026

review268331003 updated at https://codereview.tryton.org/268331003/#ps266351003

review268331003 updated at https://codereview.tryton.org/268331003/#ps274351003

review268331003 updated at https://codereview.tryton.org/268331003/#ps266411002

New changeset 8678057b3768 by Nicolas ?vrard in branch 'default':
Modularize code in GroupLines wizard
https://hg.tryton.org/modules/account/rev/8678057b3768

added 1 deleted label and removed 1 deleted label

closed

New changeset d7bcff233505 by Nicolas ?vrard in branch 'default':
Modularize code in GroupLines wizard
https://hg.tryton.org/tryton-env/rev/d7bcff233505