Change Preference accessor to use category property. Build accessor from accessor holder accessors and not from properties.

Conflicts:
	product/ERP5Form/tests/testPreferences.py

bug #20160107-9E3B60

Fix property name for skin layer ordering on the skin folder.

See also http://git.erp5.org/gitweb/neoppod.git/commitdiff/54d692c?js=1
("client: drop monkey-patch that is not mandatory anymore for NEO")

this restore the behaviour of the code before commit 8e073789

Also methods without a security declaration should not be added.

Rewrite Base_getPossibleWorkflowActionItemList by External Method instead of Python Script having a Manager proxy role.

Because now proxy role in script affects workflow transition guard checks.

because we loose existing roles in proxy role scripts and init scripts require Owner role in context.

because it is called from unrestricted method : builder._searchMovementList().

Avoid listbox with parameters from selection