* lisp/frameset.el: Miscellaneous cleanups.

* lisp/frameset.el: Miscellaneous cleanups.
  (frameset): Add docstring.  Move :version property to its
  own `version' slot.
  (frameset-copy): Rename from copy-frameset.
  (frameset-p): Check more thoroughly.
  (frameset-prop): Do not check for :version, which is no longer a prop.
  (frameset-live-filter-alist, frameset-persistent-filter-alist):
  Use new :never value instead of t.
  (frameset-filter-alist): Expand and clarify docstring.
  (frameset-filter-tty-to-GUI, frameset-filter-sanitize-color)
  (frameset-filter-minibuffer, frameset-filter-save-param)
  (frameset-filter-restore-param, frameset-filter-iconified):
  Add pointer to docstring of frameset-filter-alist.
  (frameset-filter-params): Rename filter values to be more meaningful:
  :never instead of t, and reverse the meanings of :save and :restore.
  (frameset--process-minibuffer-frames): Clarify error message.
  (frameset-save): Avoid unnecessary and confusing call to framep.
  Use new BOA constructor for framesets.
  (frameset--reuse-list): Doc fix.
  (frameset--restore-frame): Rename from frameset--get-frame.  Doc fix.
  (frameset--minibufferless-last-p): Rename from frameset--sort-states.
  (frameset-minibufferless-first-p): Doc fix.
  Rename from frameset-sort-frames-for-deletion.
  (frameset-restore): Doc fixes.  Use new function names.
  Most changes suggested by Drew Adams <drew.adams@oracle.com>.

* lisp/desktop.el (desktop-clear): Use new name of sort predicate.