** Changes in Allout

*** Topic cryptography added, enabling easy gpg topic encryption and
decryption.  Per-topic basis enables interspersing encrypted-text and
clear-text within a single file to your heart's content, using symmetric
and/or public key modes.  Time-limited key caching, user-provided
symmetric key hinting and consistency verification, auto-encryption of
pending topics on save, and more, make it easy to use encryption in
powerful ways.  Encryption behavior customization is collected in the
allout-encryption customization group.

*** `allout-view-change-hook' marked as being deprecated - use
`allout-exposure-change-hook' instead.  Both are still invoked, but
`allout-view-change-hook' will eventually be ignored.  The new
`allout-exposure-change-hook' is called with args that were passed to
`allout-flag-region', making it easier to use.

*** Other allout functions which change the outline structure also have
hooks, enabling cooperative allout enhancements.  See
`allout-structure-added-hook', `allout-structure-deleted-hook', and
`allout-structure-shifted-hook'.

*** Default command prefix changed to "\C-c " (control-c space), to avoid
intruding on user's keybinding space.  Customize the
`allout-command-prefix' variable to your preference.

*** Allout now uses text overlay's `invisible' property (and others) for
concealed text, instead of selective-display.  This simplifies the code, in
particular avoiding the need for kludges for isearch dynamic-display,
discretionary handling of edits of concealed text, undo concerns, etc.

*** Some previously rough topic-header format edge cases are reconciled.
Level 1 topics use the mode's comment format, and lines starting with the
asterisk - for instance, the comment close of some languages (eg, c's "*/"
or mathematica's "*)") - at the beginning of line are no longer are
interpreted as level 1 topics in those modes.  (Yay!)

*** Many or most commonly occuring "accidental" topics are disqualified.
Text that looks like low-depth topics is no longer mistaken for them unless
the depth of the first subsequent topic-seeming text greater depth is only
one level deeper.

For example, pasting some text with a bunch of leading asterisks into a
topic that's followed by a level 3 or deeper topic will not cause the
pasted text to be mistaken for outline structure.  Likewise for any text
added that looks like any level 2 or 3 topics.

This settles an old issue where typed or pasted text needed to be carefully
reviewed, and sometimes doctored, to avoid accidentally disrupting the
outline structure.  Now that should be generally unnecessary, as the most
prone-to-occur accidents are disqualified.

*** Many substantial fixes and refinements, including:

   - repaired regexp-quoting of custom header prefixes, so any literals
     will now work (for instance, mathematica's "(*" is now properly
     accepted).
   - repaired inhibition of inadvertent edits to concealed text.
   - refuse to create "containment discontinuities", where a
     topic is shifted deeper than the offspring-depth of its' container
   - auto-fill-mode is now left inactive when allout-mode starts, if it
     already was inactive.  also, `allout-inhibit-auto-fill' custom
     configuration variable makes it easy to disable auto fill in allout
     outlines in general or on a per-buffer basis.
   - mode hook changes: new hook `allout-mode-deactivate-hook', for
     coordinating with deactivation of allout-mode.  `allout-mode-hook' is
     now run after the `allout-mode' variable is changed, as is the new
     `allout-mode-deactivate-hook'.
   - allout now tolerates fielded text in outlines without disruption.
   - hot-spot navigation now is modularized with a new function,
     `allout-hotspot-key-handler', enabling easier articulation and
     enhancement of the functionality by allout addons.
   - topic body navigation is easier, where repeated beginning of line and
     end of line key commands cycle through the actually beginning/end of
     line and then beginning/end of topic, etc.  see new customization vars
     `allout-beginning-of-line-cycles' and `allout-end-of-line-cycles'.
   - repaired retention of topic body hanging indent upon topic depth shifts
   - bulleting variation is simpler and more accommodating, both in the
     default behavior and in ability to vary when creating new topics
   - mode deactivation now does cleans up effectively, more properly
     restoring affected variables and hooks to former state, removing
     overlays, etc.  see `allout-add-resumptions' and
     `allout-do-resumptions', which replace the old `allout-resumptions'.
   - included a few unit-tests for interior functionality.  developers can
     have them automatically run at the end of module load by customizing
     the option `allout-run-unit-tests-on-load'.
   - many, many minor tweaks and fixes.  many internal fixes and
     refinements of docstrings.
   - version number incremented to 2.2