With unintrusive error dialogs gone, we can cut some unnecessary bits
out of EActivity.
I'm also adding a new enum property called "state", which is one of:
E_ACTIVITY_RUNNING
E_ACTIVITY_WAITING
E_ACTIVITY_CANCELLED
E_ACTIVITY_COMPLETED
The state of an activity must be explicitly changed. In particular,
when the user cancels an activity the state should be set only after
confirming the operation has been cancelled and not when cancellation
is requested (e.g. after receiving a G_IO_ERROR_CANCELLED, not when
the GCancellable emits "cancelled"). EActivityBar and EActivityProxy
widgets have been updated to make this distinction clearer in the UI.
E_ACTIVITY_WAITING will be used when activities have to be queued and
dispatched in sequence, which I haven't written yet.
'Send' and 'Save Draft' are now asynchronous and run outside of
Evolution's MailMsg infrastructure.
Add an EActivityBar to the composer window so these asynchronous
operations can be tracked and cancelled even in the absense of a main
window. Also add an EAlertBar to the composer window so error messages
can be shown directly in the window.
Instead of calling e_alert_dialog_run_for_args(), call e_alert_submit()
and pass the EMsgComposer as the widget argument. The EMsgComposer will
decide whether to show an EAlertDialog or use the EAlertBar, depending
on the GtkMessageType of the alert.
