Calling an external python will prevent calling navigate from a python script
with a proxy role.

This is a followup to commit 8995b645
("always start transactions with begin() and make tic() commit automatically"):
there is now no need to use self.stepTic() instead of self.tic()

PayZen interface expectes all dates in UTC, but suds library is not configurable.
So force UTC usage while importing and using suds, so no date mangling will happen.

datetime.datetime is required, not Zope-ish DateTime.
there is no conversion in dict anymore.

In case of navigate the caller is responsible for providing date as text string.

suds library understands datetime.datetime objects, so do *NOT* convert them
to strings.

Add portal_secure_payments if not exists.

Cover basic _getSignature cases.

Have only one method for signature calculation and a bit of data modification:
_getSignature

Use method introspection to manipulate fields, fallback to strings later.

Accept DateTime objects for dates.

Implement soap_duplicate.

Really never raise (trust no one). Always return excepted values in order
to not trick caller.

Non transmitted values shall result in ++
Empty (evaluated to None) values shall result in ++

Caller might try to log the transmission XMLs and raising would result in
aborted transaction.

Dates in signature have to be in %Y%m%d format.

Note: Signatures still do not match.

Also document method a bit.

Instead of doing analysis of passed dict, just accept payzen_dict, which will
be blindly applied.

Split to more methods, in order to have proper separation and being able to
test critical parts.

How data will be corelated with service shall be implemented on caller level.
Thanks to this no additional requirements are added.

Allow to pass page_template which will be run in context of temporary object
with all required parameters.

Delegate responsiblity of dynamic data preparation to caller, check only service
consistency.

This reverts commit a91456c9.

Conflicts:

	bt5/erp5_payzen_secure_payment/bt/revision

This reverts commit e5b9bfac.

This reverts commit e1356f85.

It is required to give maximum extensibility to web site developer of payzen
based shop.