* lisp/bindings.el (ctl-x-r-map): Bind ?f to frameset-to-register.

* lisp/bindings.el (ctl-x-r-map): Bind ?f to frameset-to-register.

* lisp/register.el: Add support for framesets.
  (frameset-frame-id, frameset-frame-with-id)
  (frameset-p, frameset-restore, frameset-save): Declare.
  (register-alist): Document framesets.
  (frameset-session-filter-alist): Declare.
  (frameset-to-register): New function.
  (jump-to-register): Implement jumping to framesets.  Doc fix.
  (describe-register-1): Describe framesets.