This is a terse description of the new features added to readline-6.2 since
the release of readline-6.1.

a.  The history library does not try to write the history filename in the
    current directory if $HOME is unset.  This closes a potential security
    problem if the application does not specify a history filename.

b.  New bindable variable `completion-display-width' to set the number of
    columns used when displaying completions.

c.  New bindable variable `completion-case-map' to cause case-insensitive
    completion to treat `-' and `_' as identical.

d.  There are new bindable vi-mode command names to avoid readline's case-
    insensitive matching not allowing them to be bound separately.

e.  New bindable variable `menu-complete-display-prefix' causes the menu
    completion code to display the common prefix of the possible completions
    before cycling through the list, instead of after.