Third version of this series [0].  I've made some changes in this
version:

* added a new crypto.c that holds two functions: one to return a
  context for a specified crypto protocol (and initialize it if
  needed), and another to cleanup a crypto struct.  This is introduced
  in the first patch, and makes the rest of the patches a little
  cleaner.

* Based on Jani's and Daniel's suggestion, I decided to leave the
  notmuch_show_params_t in notmuch-reply.c, since we might need it
  later and it's less changes here.

Otherwise everything else is the same.  I think the version is nicer
that the previous ones.

FWIW I also now have S/MIME support working based on this patch
series.  Daniel has kindly agreed to put together some tests for that,
so once this series is accepted and Daniel's tests are sent, I'll send
on the rest of the S/MIME support (which is actually just one small
patch on top of this series).

jamie.

[0] id:"1337205359-2444-1-git-send-email-jrollins@finestructure.net"
    id:"1337362357-31281-1-git-send-email-jrollins@finestructure.net"