Bump version number and add NEWS file.

Make sure the user is fine with overwriting an existing file. If
the user selects a file with the file chooser dialog, then the
dialog takes care of asking for confirmation. Otherwise, if the
user does not change the default filename, then we need to
explicitly ask for confirmation.

Do not display the full pathname on the output button label, but
only the basename.

Add a button to fire up a file chooser dialog to select the name
of the encrypted or signed file to write.

Add an option to generated armored ASCII output instead of the
default binary output.

Allow the user to search through the list of public key for a
given user ID (or a user ID matching the searched string).

Add a rudimentary man page for the yki program.

Provide two desktop files conforming to the DES-EMA
specification to add context menu entries to libfm-based
file managers.

Assign a title to the encrypt/sign dialog.

Disable the OK/Confirm button until a workable action (sign and/or
encrypt) has been defined by the user. Also only enable the
detached signature button when it makes sense, i.e. when signing
is enabled and encryption is disabled.

Refactor the code to get rid of the yki_ctx_t structure, which is
replaced by a yki_encrypt_data_t structure that is internal to
the encrypt module.

Move all code related to encryption or signing to a dedicated
module. Leave only option parsing to the main yki module.

Use a dedicated module to store the yki_ctx_t structure and
associated helper functions. Also rename the structure from
the original yorkie_ctx_t to yki_ctx_t for consistency.

Move most of the code out of the main function; only keep the
code for option parsing, error reporting, and freeing resources.

Implement command line parsing with GLib's parser. Two options
are available for now: -e to encrypt (and/or sign) and -d to
decrypt (and/or verify). Encrypt is the default mode and is the
only one supported for now.

Report runtime errors through GLib's GError framework. Also make
sure to free resources before exiting.

Add a module dedicated to helper functions to work with GpgME.
This module provides a small structure encapsulating both a
stdio FILE object and a GpgME data buffer.

Explain briefly what Yorkie is about and explicitly list the
required dependencies.

Move the bulk of the code doing the actual job in two separate
functions out of the main function.

Error out if an issue occurs either when initializing GPGME or
when building the list of public keys.

Use the gtk_dialog_run function to display the encrypt dialog.
This make things slightly easier as we no longer need to connect
callbacks to the `clicked` signal from the buttons or the
`destroy` signal from the dialog.

When building the list of public keys, exclude keys that cannot
be used for encryption for any reason.

This is Yorkie, a task-oriented graphical frontend for GnuPG.