Proof of concept: S-Expression format

This patch shows how to add a new output format to notmuch-search.c. As an example, it adds S-Expressions. The concrete formatting can easily be changed, this is meant as a proof of concept that the changes to core notmuch code are very few and all formatting state is kept inside sprinter-sexp.c.

Re: Proof of concept: S-Expression format

This patch shows how to add a new output format to notmuch-search.c. As an example, it adds S-Expressions. The concrete formatting can easily be changed, this is meant as a proof of concept that the changes to core notmuch code are very few and all formatting state is kept inside sprinter-sexp.c.