New strip-export noweb header argument value
* lisp/ob-exp.el (org-babel-exp-src-block): Strip noweb references on
export when "strip-export".
* lisp/ob.el (org-babel-common-header-args-w-values): New noweb
header value.
(org-babel-merge-params): New noweb header value.
(org-babel-noweb-p): New noweb header value.
* testing/examples/babel.org (an): Testing new noweb header value.
* testing/lisp/test-ob-exp.el (ob-exp/noweb-strip-export-ensure-strips):
Testing new noweb header value.
* doc/org.texi (noweb): Document new noweb header value.