Update to 2.3.26, and enable many more features by default.

Changes:
* Balsa-2.3.26 release. Release date 2008-09-07

- composing format=flowed messages with spaces pasted in works better.
- allow to explicitly specify a GPG key id for an identity.

* Balsa-2.3.25 release. Release date 2008-06-14

- GMail compatibility.
- notification icon in GNOME panel is optional now.
- wrapping of flowed text improved.
- lots of various bug fixes.

* Balsa-2.3.24 release. Release date 2008-05-31

- Support for accessing files over gnome-vfs (smb, ssh mounts, etc.)
- maildir tree scanning fixes.
- Rudimentary support for sending text/html messages.
- UIDPLUS IMAP extension support.

* Balsa-2.3.23 release. Release date 2008-03-20

- Suppport for IMAP MULTIAPPEND extension for faster uploading of
  message batches to and from IMAP servers.
- improved scanning of mailbox trees.
- GtkSourceView2 support.

* Balsa-2.3.22 release. Release date 2007-12-23

- new address edition widget in the compose window.
- compose window displays languages available for spell checking.
- more new icons.

* Balsa-2.3.21 release. Release date 2007-12-08

- migration from GnomeUI to GtkUIManager
- Rubrica address book support.
- bugs fixed: GNOME: 481842, 488432, 496316; Redhat: 414361.

* Balsa-2.3.20 release. Release date 2007-09-07

- fix buffer overflow (#474366).
- avoid sending messages twice under certain conditions.

* Balsa-2.3.19 release. Release date 2007-08-25

- more build fixes.

* Balsa-2.3.18 release. Release date 2007-08-22

- reflow improvements.
- Build problems against steaming-hot GNOME fixed.
- Make BINARY and ESEARCH IMAP extensions usage more robust.

* Balsa-2.3.17 release. Release date 2007-07-04

- check validity of server APOP challenge.
- add ability to store VCARD signatures.
- use ESEARCH IMAP extension if available.
- message wrapping fixes.
- and an usual bunch of bugfixes.

* Balsa-2.3.16 release. Release date 2007-05-27

- fix message threading regression.
- reorganize "Identity" dialog.
- code cleanup.

* Balsa-2.3.15 release. Release date 2007-05-01

- Use GtkPrint infrastructure if available.
- handle LDAP referrals.
- nicer citation marks.
- initial libnotify support.
- IMAP BINARY support.

* Balsa-2.3.14 release. Release date 2006-12-12

- deferred population of the mailbox index.
- client-side IMAP sorting.
- be compatible with recent gtk2 releases.
- mailbox tabs reorderable with d&d.
- enhanced mailto: URL handling.

* Balsa-2.3.13 release. Release date 2006-06-26

- many small fixes
- nicer icons.

* Balsa-2.3.12 release. Release date 2006-03-04

- do not reference freed memory in mbox driver.

* Balsa-2.3.11 release. Release date 2006-02-28

- assure messages are properly signed after identity change.
- Ctrl-N goes over unread messages in all mailboxes.
- Redone Preference Manager.
- support better slow LDAP servers.
- use better real estate when displaying message counts.
- fixed bugs: 330085, 330093, 332980.

(wiz)