Added a mime part viewer for attachments

[Philip Van Hoof <spam pvanhoof be>]

Hi there partners in crime,

I added a mime part view for attachments and integrated it with both the
TnyGtkMsgView and the TnyMozEmbedMsgView (the second obviously came
automatically because that one simply inherits the first and calls the
super method to create already supported mime part viewers).

The attachment mime part view for Gtk+ reuses the TnyGtkAttachListModel
and the TnyGtkMsgView has a GtkIconView ready (just like the good old
days, the day before yesterday, when the new TnyMimePartView concept
wasn't yet introduced).

This reintroduced the support for attachments in the demo user interface
of course.

The implementation is of course, as usual, simple:

http://svn.tinymail.org/svn/tinymail/trunk/libtinymailui-gtk/tny-gtk-attachment-mime-part-view.c


Saving the attachments crashes. I will obviously fix that situation. It
probably has something to do with the TnySaveStrategy instances not
being yet configured when the mime part views are created or maybe
something with the popup handler.

The idea is actually to allow inheriting the TnyGtkMsgView type, so that
you can provide an implementation that will call the save method on the
strategy. For that I will need to make the strategy a read/write
property rather than a write-only one, like how it's now, so that the
inherited type has access to the strategy instance.

Blerp ... I'll fix all that soon (or maybe you can go ahead, dear
reader). It would be nice to have people who are actually building a
client on top of tinymail telling me what I'm making too hard and stuff
like that. I don't really get an awful lot of feedback about Modest, for
example, Dirk.

Please do tell me about what can be made simpeler. For example which
methods should become virtual. Things like that.


-- 
Philip Van Hoof, software developer
home: me at pvanhoof dot be
gnome: pvanhoof at gnome dot org
work: vanhoof at x-tend dot be
blog: http://pvanhoof.be/blog