[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*