knowledge_pad: fix resubmit of gadget preference

Step to reproduce:
- change preferences once
- go back to previous page with browser button
- submit again
- exception in KnowledgeBox_baseEdit because 'form_id' is sent twice
  and is transformed by Zope into a list
Add support for default value in category & value accessors

In Base._getAcquiredCategoryMembershipItemList, replace broken code by an exception.
add asComposedDocument.getProperty().

that tries to get the property from the original and its effecive models.
stop copying (deprecated) Payment Condition documents from Trade Condition to Order, and from Order to Packing List.
Formulator: Add a FloatField validator to take account of the precision and the user input length.
add possibility to use a SQLConnection from integration site / web service tool
make possible to import Conduit from portal_components
fixup! stop copying (deprecated) Payment Condition documents from Trade Condition to Order, and from Order to Packing List.
Mail Message: prevent sending email twice in case of conflict errors

* Method is activated with max_retry 0 and no retry on conflict error
* Document is not modified in case of multiple recipients
fixup! credentials: only take into account persons with reference when looking up login from email
Alarm check skin cache added to erp5_administration

This alarm will check if a cache is assigned to some files in portal_skins.
If a file has no cache manager, it triggers a Problem.
When solving the alarm, `http_cache` will be assigned to uncached files.

Conflicts:
	bt5/erp5_administration/bt/revision
erp5_accounting_l10n_de_skr04: Update most important categories to 2012 version of SKR04 and correct wrong title "Deutch" to "Germany".
erp5_accounting_l10n_de_skr04: Remove unused skr04 categories
it syncml table does not exist, create it
make indexation of document into syncml works even for data coming from integration modules
remove some iHotFix references
LiveTest: remove unused code
LiveTest: use independant requests for each test method
LiveTest: set a default value for initial_transaction_hash so that _close does not fail when setUp has failed
LiveTest: use self.portal instead of getPortalObject