Log Message:
Update to 0.9.6.

* A crash bug when deleting currently opened folder has been fixed.
* The performance issue of the address book has been fixed.
* The behavior of manual signature insertion has been reverted.
* A crash bug on startup when a font can't be loaded has been fixed.
* The format of MIME boundary has been modified again.
* Other minor bugfixes have been made.

ok'ed by chris@