refactor form error handling:
* almost everything is in the base form class, with other form errors related code
* deprecate form_field_error in favor of field_error and format_error on the renderer
* fix pb with js localization of errors by properly using field.role_name()
* rename 'errors' into 'error' in forminfo to avoid confusion
[MESSAGES CONTROL]
disable-msg = C0301
[VARIABLES]
# Enable / disable this checker
enable-variables = yes
additional-builtins = _, display_name
[BASIC]
required-attributes=
attr-rgx = (w|[a-z_][a-z0-9_]{2,30})
variable-rgx = (w|[a-z_][a-z0-9_]{2,30})$
argument-rgx = (w|[a-z_][a-z0-9_]{2,30})$
[TYPECHECK]
generated-members=debug,info,notice,warning,error,critical,exception