A header type
Tinymail 1.0
http://tinymail.org/API/libtinymail-1.0/libtinymail-tny-header.html
About
This type can be used in two contexts: either a header that is attached to a TnyMsg, or a summary item that is showed in a summary view (TnyGtkHeaderListModel and TnyGtkHeaderTreeModel).
You can't create these yourself: you have to get the header of a TnyMsg using tny_msg_get_header. The implementation of this API will create the instance for you, if that is necessary.
For showing summary you have the tny_folder_get_headers API which will prepend TnyHeader instances into your TnyList.
