[erp5_web_renderjs_ui] Update website modification, to prevent launcher gadget modification date to be more recent

- WebPage_exportAsSingleFile
- WebPage_extractReferredObjectDict

when converting an image, the returned value of img.convert
is not everytime a string. It might be a kind of acquisition
value

testTask: new test to check that simulation inheritance can overwrite default ledgers set on portal type

testAccounting: makes test_createBalanceOnLedgerWithTransactionsWithNoLedger closer from Delivery Type expected behaviour

Add allow_tag_list and deny_tag_list parameter to WebPage_extractReferredObjectDict

HTML rendering tolerates list value, and renders are multi-lines.
Do the same in ODT renderer.

disable derived_merge in a query where it may cause the wrong result, instead of using DISTINCT trick.

* normalize URL in a case where we have several languages in URL.
* redirect to the web site root if HTTP_REFERER is not set.

erp5_web: set relative url path as absolute if no base_url found in WebPage_extractReferredObjectDict

This merge request makes full use of the base category "Ledger" in the Accounting and Project modules of ERP5.

Main modifications are : 
   * Adding the ledger property on every Accounting Transaction Types. It was already on Task Types.
   * Adding a new portal type of portal type for the types quoted above. It allows to define a list a ledgers directly on these types. These ledgers are the one allowed on the documents of each type.
   * New Delivery_init (Python) Script called by every "${}_init" script of the above type, and setting a default ledger at the creation of the documents
   * Adding a ledger field and column in the view defined like "[Entity|Account|...]_viewTransactionList" to only display the transactions belonging to a favorite ledger. The favorite ledgers can be defined in the Accounting Preferences. The list of displayed ledgers is the list of ledgers defined on the accounting portal types. If no ledger is defined, the field doesn't show up.
   * Adding a ledger field in every accounting report, to only generate them with the movements belonging to the ledgers of one's choice.
   * Adding the ledger parameter (and co) to the InventoryAPI to ease the queries on Inventory by ledger. Please note that the stock table now embeds a "ledger_uid" column


/reviewed-on nexedi/erp5!129

erp5_accounting: closing an Accounting Period generates one Balance Transaction per accounting ledger

BalanceTransaction.py updated to correctly index Balance Transactions with their ledgers.
_computeStockDifferenceList also now returns a correct result

erp5_mysql_innodb_catalog, erp5_research_item: Removes the parent_ledger related key and the code depending on it

erp5_accounting: adds "ledger" in the extra columns of AccountingTransactionModule_viewAccountingTransactionList