[O] Add the capture feature "%(sexp)" to org-feed

[Michael Brand]

Hi all

I am almost done with adding the capture feature "%(sexp)" to
org-feed.el. Because for this I would like to use
org-capture-escaped-% from org-capture.el in org-feed.el I renamed
this function to org-template-escaped-% and call it in org-feed.el.
The only thing what is missing is that unless I do some manual
evaluations before, there is still "Symbol's function definition is
void: org-template-escaped-%". For this I would like to ask for some
design and implementation guidance, if available also where I should
read in the elisp reference manual or wherever.

Michael