* camel-uid-cache.c: New code to keep an on-disk cache of what
UIDs have been seen in a folder.
* camel-provider.h: Add new flags CAMEL_PROVIDER_IS_SOURCE (mail
can arrive in it by non-Camel means) and CAMEL_PROVIDER_IS_STORAGE
(you can work with mail directly without needing to copy it local).
* providers/*/camel-*-provider.c: Add flags as needed: imap and
mbox are SOURCE and STORAGE. mh and nntp are just STORAGE, pop3 is
just SOURCE.
* camel-mime-message.c (process_header): Add another subject
g_strstrip that fejj's earlier commit missed.
svn path=/trunk/; revision=4616
