API change

[Philip Van Hoof <spam pvanhoof be>]

I renamed TnyGetHeadersCallback and TnyGetHeadersStatusCallback to TnyRefreshFolderCallback and TnyRefreshFolderStatusCallback. I also renamed the interface function pointer refresh_headers_async_func on TnyMsgFolderIface to refresh_async_func and I renamed the public interface method tny_msg_folder_iface_refresh_headers_async to tny_msg_folder_iface_refresh_async. I also added a tny_msg_folder_iface_refresh API which uses refresh_func as function pointer in the TnyMsgFolderIface type.

If you have any questions: shoot or first look at the TnySummaryView type in the demo-ui. It only got more simple and convenient.

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