[MERGE] various bugfixes/improvements (coming from EDI development)

 - _original_module is now available on model/browse_records
 - context usage in res.partner.*
 - proper name_search() + default values for res.currency
 - active_model in wkf exec context
 - safe_eval allows try/except/finally
 - yaml_import: !ref {id: xml_id} works
 - ir_mail_server: support for alternative body/subtype
 - default value for web.base.url config parameter
 - consistency rename: Model.*get_xml_id* -> *get_external_id*

bzr revid: odo@openerp.com-20111005100954-c8mbd4kz6kkqaj84