Because the helper script for invoice, (order, packing lists, etc) printout is using `DateTime.strftime` it does not support dates before 1900.
This is a [documented behavior](https://docs.python.org/2/library/datetime.html#strftime-and-strptime-behavior) in python that dates before 1900 cannot be used.

In these cases it's not supposed to happen, but if by mistake user enter a date before 1900, printing the invoice would fail, which is not good.

These patterns were very simple and did not need strftime.

/reviewed-on !694

/reviewed-on nexedi/erp5!689

is used in Folder_delete, in order to decide if we would delete the object from ZODB
or do workflow transition.

Previous code was not harmful, since isDeletable check above would block
the case of existing workflow with 'delete_action' not possible in current state.
Yet, it was confusing.

/reviewed-on !696

Update Colors to patio colors

![Screenshot_2018-06-11_at_17.02.16](/uploads/d0ebc58a32df69a359e3023383fcfec2/Screenshot_2018-06-11_at_17.02.16.png)


/reviewed-on nexedi/erp5!693

See 4bb5d32e

Do not rely on DateTime.strftime which does fails on dates <= 1900.
This simple case does not need all the features of strftime and can be
implemented inline.

It currently fails with such ValueError:
```
year=101 is before 1900; the datetime strftime() methods require year >= 1900
```

Some dialog expect to get the line uid list, even if no cell was directly editable.

Use the same dialog pattern than the mass transition dialog.
Display all documents by using the current query + deletable workflow state.

Use the listbox_uid to get the effective list of document to delete.

This partially revert nexedi/erp5@490af3ba

/reviewed-on nexedi/erp5!688

Add the portal type "DSN Disenrollment Record" for this

Used to record details about the end of a contract to report in social declarations.

/reviewed-on nexedi/erp5!692