(allout-prior-bindings, allout-added-bindings): Remove, after long deprecation.

(allout-prior-bindings, allout-added-bindings): Remove, after long deprecation.
(allout-beginning-of-line-cycles, allout-end-of-line-cycles):
Add customization vars controlling allout-beginning-of-line and
allout-end-of-line conveniences.
(allout-header-prefix, allout-use-mode-specific-leader)
(allout-use-mode-specific-leader, allout-mode-leaders): Revised docstrings.
(allout-infer-header-lead): Change to be an alias for
allout-infer-header-lead-and-primary-bullet.
(allout-infer-header-lead-and-primary-bullet): New version of
allout-infer-header-lead which assigns the primary bullet to the
same as the header lead, when its being changed.
(allout-infer-body-reindent): Apply regexp-quote instead of unconditionally
prepending "\\", so that all literal allout-header-prefix and
allout-primary-bullet strings are properly handled.
(allout-add-resumptions): Add optional qualifier for extending or appending to
existing values, rather than replacing them.
(allout-view-change-hook): Clarify docstring.
(allout-exposure-change-hook): Take explicit arguments, via run-hook-with-args.
(allout-structure-added-hook, allout-structure-deleted-hook)
(allout-structure-shifted-hook): New hooks analogous to
allout-exposure-change-hook for other kinds of structural outline edits.
(allout-encryption-plaintext-sanitization-regexps): New encryption
customization variable, by which cooperating modes can provde massage of the
plaintext without actually being passed it.
(allout-encryption-ciphertext-rejection-regexps)
(allout-encryption-ciphertext-rejection-ceiling): New encryption
customization variables, by which cooperating modes can prohibit rare but
possible ciphertext patterns from fouling their operation, with actually being
passed the ciphertext.
(allout-mode): Run activation and deactivation hooks after the minor-mode
variable has been toggled, to clarify the mode disposition.  The new encryption
ciphertext rejection variable is used to ensure that the ciphertext does not
contain text that would be recognized as outline structural elements by allout.
Substite allout-beginning-of-line and allout-end-of-line for conventionall
beginning-of-line and end-of-line bindings. If allout-old-style-prefixes is
non-nil, don't nullify it on mode activation!
(allout-beginning-of-line): Respect `allout-beginning-of-line-cycles'.
(allout-end-of-line): Respect `allout-end-of-line-cycles'.
(allout-chart-subtree): Implement new mode, charting only the visible items in
the subtree, when new 'visible' parameter is non-nil.
(allout-end-of-subtree): Properly handle the last item in the buffer.
(allout-pre-command-business, allout-command-counter): Increment an advertised
counter so that cooperating enhancements can track revisions of items.
(allout-open-topic): Run allout-structure-added-hook with suitable arguments.
(allout-shift-in): Run allout-structure-shifted-hook with suitable arguments.
(allout-shift-out): Fix doubling for negative args and ensure call of
allout-structure-shifted-hook by solely using allout-shift-in.
(allout-kill-line, allout-kill-topic): Run allout-structure-deleted-hook with
suitable arguments.
(allout-yank-processing): Run allout-structure-added-hook with proper arguments.
(allout-yank): Enclose activity in allout-unprotected.
(allout-flag-region): Run allout-exposure-change-hook with suitable arguments,
instead of making the callee infer the arguments.
(allout-encrypt-string): Support
allout-encryption-plaintext-sanitization-regexps,
allout-encryption-ciphertext-rejection-regexps, and
allout-encryption-ciphertext-rejection-ceiling.  Indicate correct
en/decryption mode in symmetric encryption failure message.
(allout-obtain-passphrase): Use copy-sequence to get a distinct copy of the
passphrase, and don't zero it or we'll corrupt the stashed copy.
(allout-create-encryption-passphrase-verifier)
(allout-verify-passphrase): Respect the new signature for allout-encrypt-string.
(allout-get-configvar-values): Convenience for getting a configuration variable
value and handling its absence gracefully.