cylc gui: fix gtk warning for toolbar.

GTK versions 2.20+ produce a warning when cylc gui
is loaded, due to the use of a gtk.HBox in the
toolbar (in a gtk.ToolButton). This seems OK from
the documentation (and works fine) but it seems that
the GTK code is set up to only be happy with a
gtk.Misc object - e.g. a gtk.Image.

We used a gtk.HBox for the iconwidget in the
layout toolbutton (toggle side-by-side) so that we
could have a left and a right arrow - this now
has to be changed. Given that we can only use one
of these (only a single gtk.Image), I've moved this
to the View 2 toolbar to make it clearer.
Don't catch failed job submission prematurely.
isodatetime: update: recurrence membership
isodatetime: fix bug: #25
Merge pull request #900 from benfitzpatrick/cylc-gui.fix-toolbar-gtk-warning

cylc gui: fix gtk warning for toolbar.
Merge pull request #904 from benfitzpatrick/isodatetime.update-recurrence-membership

isodatetime: update recurrence membership
Remove "at unknown-time" from poll results.
Compile the poll suffix regex.
Added a test for state change on task poll result.
Merge pull request #906 from hjoliver/fix-poll-result-handling

Remove "at unknown-time" from poll results.
Merge pull request #901 from hjoliver/fix-job-submission-bug

Don't catch failed job submission prematurely.
Set initial global verbosity flag.
Merge pull request #908 from hjoliver/global-verbose-flag-init

Set initial verbosity flag.
Updated change log for 5.4.10.
Merge branch 'master' into multi-processing

Conflicts:
	lib/cylc/flags.py
	lib/cylc/job_submission/job_submit.py