[etwist] fix handling of multiple files per field html5 permits multiple files uploads, which can be expressed as:: <input type='file' multiple='multiple' /> This changeset avoids previous crash. Nothing is changed when a single file is uploaded (backward compat is thus preserved). When multiple files are uploaded for a single html input tag, the corresponding web request form key receives a list of tuples like [('filename-1', IStream1), ('filename-2', IStream2), ...]. closes #2847207.

[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