xgettext: Improve support for specialized vector syntax in Scheme.
Reported by Florent Angly <Florent.Angly@cslbehring.com>.
* gettext-tools/src/x-scheme.c (read_object): Don't call free_token on an
uninitialized token. Support recent syntax for homogeneous vector types (SRFI-4)
and byte vectors as well.
* NEWS: Mention the change.
