[FIX] session expired
[FIX] web: openerpframework.js: do not use _.str

openerpframework.js can be used as standalone library (im_livechat uses
it this way) and do not depend on underscore.string.js
Merge branch 'master' of bzr::lp:~openerp/openerp-web/saas-2 into ocb-saas-2