add CamelExceptions to several functions. Use camel_session_new to
* camel-session.h:
* camel-session.c: add CamelExceptions to several functions. Use
camel_session_new to initialize the session and URL fields of
created CamelStores as appropriate.
* camel-store.h:
* camel-store.c
* camel-service.h:
* camel-service.c: Move the session and url (and associated
functions) from CamelStore to CamelService. Add url_flags to
CamelService so subclasses can specify which URL components
are mandatory for them. Add camel_session_new for
camel_session_get_store* to use.
* providers/mbox/camel-mbox-folder.c:
* providers/mbox/camel-mbox-store.c:
* providers/mbox/camel-mbox-store.h: Update for above changes.