clear _expected dict when callback is called. This way when another stanza arrives with the same id, it isn't catched as expected.

preferences window is created on the fly like every other window (well apart from FT [TODO for that]); this is good as we do not want such window to sit in memory; also fix some border width and spacing in prefs window

when a child change his status, redraw parent line too (parent icon may depend on children status). Fixes #1649

nes DataForm design that allow each widget on each line to have different size (it means I remove the gtk.Table). Fixes #1633

don't ask twice the password when we create an account and show correct page in vcard even we receive an empty vcard. Fixes #1560

use correct JID when we receive a file-completed event depending if we send or receive the file. See #1553