Bump version number and update NEWS file.

Error out properly if we cannot open a file to attach.

Avoid Quoted-Printable encoding for attachment when possible
(if the attachment appears to be US-ASCII and does not contain any
line longer than 998 characters).

Some mail clients (Gnus?) seem to have problems extracting
attached OpenPGP keys if they are encoded in Quoted-Printable.

Bump version number; update NEWS and README.md files; update
copyright notices.

Use the latest sbuffer module from my libnotch library.

Remove unused variable and fix signed/unsigned comparison.

Do not proceed with encryption if no key can be found for a given
recipient.

Document the -E, --encrypt option in manual page.

Support simultaneous signing and encryption.

Allow the use of -E option to specify a recipient to encrypt the
message to. If several -E options are used, the message will be
encrypted to all specified recipients.

Rename signing_ctx to crypto_ctx. Accept (and silently ignore)
the -E, --encrypt option.

When a file to attach is specified by a pathname, only use the
basename (without any path components) as the attachment filename.

Nice one... Hopefully no one is using HAVAL.

Only the long forms --user-agent and --date were accepted (doh!).

Listen to GpgME if an error occured when attempting to sign, and
abort if that is the case.

Use information provided by GpgME about the hash algorithm used
in the signature instead of assuming it is always SHA-1 (it will
probably never by SHA-1 anymore...).

Do not always add the User-Agent and Date headers. Add them
only if requested by command-line options.