term->cfg is now a full copy of the Config structure, not a pointer;
and term_reconfig() now passes in a new structure which is copied
over the top. This means that the old and new structures can be
compared, and the _current_ as well as default states of auto wrap
mode, DEC origin mode, BCE, blinking text and character classes can
be conveniently reconfigured in mid-session without requiring a
terminal reset.