reset current need when the user clicks on a need in post box

The private link page currently displays information about current need from application state. Therefore, when in postbox page the user clicks on a need and is being redirect to private link page, the current need needs to be reset to the one that the user have just clicked.
Merge remote-tracking branch 'origin/feat-postbox' into feat-postbox

Conflicts:
	webofneeds/won-owner-webapp/src/main/webapp/app/postbox/postbox.js