(desktop-buffer-mode-handlers): Make
non-customizable. Add autoload cookie. Change initial value to
nil; add elements in respective modules instead. Fix doc string.
(desktop-load-file): New function.
(desktop-minor-mode-handlers): New autoloaded variable.
(desktop-create-buffer): Call minor mode handlers. Use
desktop-load-file to load major and minor mode modules prior to
checking for a handler.
(desktop-save): Don't add nil to desktop-minor-modes for minor
modes with nil function in desktop-minor-mode-table. Don't delete
desktop file before rewriting it.
(desktop-locals-to-save): Add autoload cookie. Don't make
automatically buffer-local. Add variables column-number-mode,
size-indication-mode, indent-tabs-mode,
indicate-buffer-boundaries, indicate-empty-lines and
show-trailing-whitespace.
(desktop-clear): Allow desktop-clear-preserve-buffers to contain
regexps. Don't use desktop-clear-preserve-buffers-regexp.
(desktop-clear-preserve-buffers-regexp): Delete.
(desktop-clear-preserve-buffers): Update initial value and
docstring.
(desktop-save-buffer): Fix doc string.