Subtree expand/collapse opens mailbox

[Peter Bloomfield <bloomfld eos ncsu edu>]

In the current cvs code, clicking on the expand/collapse subtree icons
opens the mailbox attached to the node (at least in an IMAP tree). This is
because the mblist_open_mailbox() call has been moved back from
select_mailbox() to mblist_button_press_cb (button == 1), where it doesn't
seem to be possible to distinguish between expand/collapse events and
mailbox selection events. Select_mailbox() has been removed.

The attached patch, against current cvs, changes src/mblist.c. It
resurrects select_mailbox(), connected to the `tree_select_row' signal,
solely for the purpose of opening the mailbox. In contrast with
`button_press_event', `tree_select_row' doesn't seem to be triggered by
clicking on the expand/collapse icon. In minimal testing (i.e., on my Cyrus
IMAP tree), the change doesn't appear to break anything.

The patch also excises balsa_mblist_signals[], which appears to be
redundant.

open-mailbox-patch.gz