[IMP] add logging when server sends data to client, also bail out early from sending addons if we know we'll have nothing to send (client requested an empty set of web addons)
[IMP] add logging when server sends data to client, also bail out early from sending addons if we know we'll have nothing to send (client requested an empty set of web addons)

akretion/openerp-server,akretion/openerp-server,akretion/openerp-server