Many of the external links found in the notmuch source can be resolved
using https instead of http. This changeset addresses as many as i
could find, without touching the e-mail corpus or expected outputs
found in tests.
Add a date/time parser to notmuch, to be used for adding date range
query support for notmuch lib later on. Add the parser to a directory
of its own to make it independent of the rest of the notmuch code
base.
Signed-off-by: Jani Nikula <jani@nikula.org>
