Updated Hebrew translation
Stop spinner from staying on while saving drafts

Robert Schroll noticed the spinner remaining active after saving a
draft occassionally.  He also noticed a GTK critical warning about
a bad id being passed to Source.remove.  Our handling of the timeout
id in the composer was lacking; this tightens it up and ensures the
value is always set to zero once the Source has been removed.
Use new ReetrantProgressMonitor for folder open: Refs bug #730483

open_remote_async() is reetrant and ProgressMonitor is not, and my
previous attempts to work around this impedence mismatch are obviously
not working.  This introduces a reentrant progress monitor for folder
opens only, although it might be useful elsewhere.
Merge branch 'master' into wip/only-incomplete
Further database improvements