[Evolution-hackers] API change in e-d-s calendar backends

[Rodrigo Moya <rodrigo novell com>]

Hi

As part of the merging of the recurreces-work-branch into HEAD, there is
an API change in calendar backends. This is in the remove_object virtual
method, which has now a new argument, "old_object". It has thus now 2
string arguments the backend needs to set before returning:

* old_object, which is the ical string of the object before it was
removed.
* object, which is the ical string of the object after being removed. Of
course, this only makes sense when removing an individual recurrence, in
which case this 'object' arg should be set to the master object with the
reference to the removed instance. When removing all instances or a
simple object, this argument just needs to be set to NULL.

I did change all the backends (http, GW, exchange) to deal with this new
argument, although I only added the code for dealing correctly with the
recurrences to the file backend. The others need that code added.
-- 
Rodrigo Moya <rodrigo novell com>