[autoform] Make RelationField.fromcardinality a class method factory Instead of having the "RelationField" class hard-coded in this factory method (thus preventing any subclass to properly use it), we make that method a classmethod and instantiate the actual class instead of the base one.

[autoform] Use fieldclass from kwargs in guess_field for non-final relations This follows up on af969080e7e6 in which a "fieldclass" kwarg has been added in EntityFieldsForm.field_by_name() before calling guess_field(). In this changeset, this value was only used for final relation but the way non-final relation actually also changed since we also use guess_field from these relation (previously, the field class specified through uicfg was instantiated directly in EntityFieldsForm.field_by_name()). So in the non-final case in guess_field() we simply try to retrieve "fieldclass" from kwargs and fall back to RelationField.

[py37] `async` is now a reserved keyword

Merge 3.26

Added tag 3.26.6, debian/3.26.6-1 for changeset 8362503a9248

[pkg] version 3.26.6

[py3] Replace unicode keyword which is unknown in python3

[skeleton] Use "py3" as tox environment instead of "py34"

Added tag 3.26.5 for changeset 76d7b0aa94d2

[pkg] Version 3.26.5