~sircmpwn/aerc

ref: dadc9bf2b3e992851d2539d6f459a4f29001e686 aerc/completer d---------
Strip trailing newline from address book entries without names

When the list of completions from the external command doesn't have
associated contact names, the email address we attempt to parse was
being terminated with a newline. Now, we strip the trailing newline if
present.
Handle MIME encoded addresses in address book

When addresses contain special characters, net/mail MIME-encodes them
to a valid RFC 5322 address for use in headers. However, these are not
pleasant for human consumption, so we decode them for use in the
completion list. Aerc properly encodes addresses when the message is
sent.

This patch also removes surrounding white space from contact names, if
present.
Add address book completion in composer

Complete email address fields in the message composer with an external
address book command, compatible with mutt's query_cmd.