- fixed: check mapi_last_result() when advising store
- added: advise main store after initializing the sink so we know if the connection supports the sink
- changed: refactored store advising

git-svn-id: https://z-push.org/svn/z-push/trunk@1365 b7dd7b3b-3a3c-0410-9da9-bee62a6cc5b5