Reuse cookie on client side in order to avoid need to pass thru parameters to
authorisation servers.

Support form_id in login_form from request as something "hidden", which can be
preprocessed as url and later passed to authentication backend.

Keep endpoint traditional_login_form in order to use old style login.

Multiple Person can come from different sources (FB, G+, BID, ...) and they
can have same email.

Running "tunctl" will result in creation of a tap interface. In order to avoid
it call it with some "-d" parameter which will make it exit fast.

Facebook and Google implementation depends on this modules.

The workflow history is long and results in memory leaks while traversal,
which consumes (forever) lot of memory  on activity nodes.

It makes delivery non writable, so just do it after all operations.

It reverted part of 721f4f27.