[devtools] make return value of get_response_header(raw=True) consistent wrt get_header(raw=True) i.e. get_response_header(raw=True) now returns the first element of the list rather than the list itself.

include *.py
include */*.py
recursive-include data *.gif *.png *.ico *.css *.js
recursive-include i18n *.po
recursive-include wdoc *