Add method to set sequence on ModelList

For now, the developer must set himself the value of the sequence field. But a method on ModelList could do that automatically by reusing the same algorithm as the other clients.

added proteus type::feature + 1 deleted label

New review43501002 at https://codereview.tryton.org/43501002/#ps1

added 1 deleted label and removed 1 deleted label

assigned to @maxx

added 1 deleted label and removed 1 deleted label

review43501002 updated at https://codereview.tryton.org/43501002/#ps20001

review43501002 updated at https://codereview.tryton.org/43501002/#ps40001

review43501002 updated at https://codereview.tryton.org/43501002/#ps60001

review43501002 updated at https://codereview.tryton.org/43501002/#ps80001

New changeset 8734e411f17e by Maxime Richez in branch 'default':
Add method set_sequence on ModelList
http://hg.tryton.org/proteus/rev/8734e411f17e

added 1 deleted label and removed 1 deleted label

closed