Don't change group value when it is not needed

The group of xxx2many must only be changed for set and set_default. Other
methods should keep the removed/deleted records but as the older group was
destroyed this information is lost.

issue3724
review3941003
Pass the action which is calling a wizard or a report

issue3675
review3581002
Replace sha widget by password

issue3713
review3791004
Fix instance test in init_selection

key could be empty but still the call must be for an instance.

issue3728
review4011002
Manage microseconds in JSON-RPC

review3671003
Add support of domain for non-relation field

issue3743
review4171003
Remove auto-refresh

issue3752
review4281002
Add index to one2many's on_change add

review2091003
issue3539
Add multiselection widget for many2many

review3951002
issue3634
Add option to show revisions

issue3678
review3671003
Fetch jquery using the same protocol as the page
Don't let default value override existing value

issue3782
review4591002
Fix Reference field with domain

issue3783
review4621002
Add missing TODO to force parent on Reference field

review4621002
Fix domain parser for empty selection

issue3785
review4571003
Add support for editable tree

review2171002
Enforce readonly on Window.Form

issue3778
review4541002
Fix _super call of Char.get
Fix Group.add when index is -1
Empty table body when reconstruct the table