add subscribed_folders.

add subscribed_folders.

2000-10-24  Chris Toshok  <toshok@helixcode.com>

	* providers/imap/camel-imap-store.h: add subscribed_folders.

	* providers/imap/camel-imap-store.c (camel_imap_store_class_init):
	fill in vtable entries for subscription functions.
	(camel_imap_store_finalize): new function, so we can free up our
	subscribed_folders hashtable.
	(camel_imap_store_init): set CAMEL_STORE_SUBSCRIPTIONS in the
	CamelStore flags, and create our subscribed_folders hashtable.
	(camel_imap_store_get_type): camel_imap_store_finalize is our
	finalize function.
	(get_folder_info): if we're looking at subscribed_only, clear out
	the subscribed_folders hashtable, use LSUB instead of LIST, and
	insert folder paths (prepended by their namespace if there is one)
	into subscribed_folders.  INBOX subscription support needs work,
	since we always show it, regardless of it's subscribed state.
	(folder_subscribed): new function.  just look up the folder_path
	in the hashtable.
	(subscribe_folder): new function.  use the imap SUBSCRIBE command,
	and if successful add it to the hashtable.
	(unsubscribe_folder): new function.  use the imap UNSUBSCRIBE
	command, and if successful remove it from the hashtable.