Patch to content.token.inc for returning multiple value textfields as [value1, value2, value3] token

I had a need to get all the values of a multiple value textfield for use in with a auto_nodetitle generated title.

This patch adds a third token [field_FIELDNAME-multiple] which returns '[value1, value2, value3]', as distinct from the default token that just returns the first value.

Patch attached.