Make a note of the recent ENGINE developments.

         *) applies to 0.9.6a (/0.9.6b) and 0.9.7

         +) applies to 0.9.7 only

  +) Minor adjustment to "rand" code. RAND_get_rand_method() now returns a

     'const' value. Any code that should be able to modify a RAND_METHOD

     should already have non-const pointers to it (ie. they should only

     modify their own ones).

     [Geoff]

  +) Made a variety of tweaks to the ENGINE code.

     - "atalla" and "ubsec" string definitions were moved from header files

       to C code. "nuron" string definitions were placed in variables

       rather than hard-coded - allowing parameterisation of these values

       later on via ctrl() commands.

     - Removed unused "#if 0"'d code.

     - Fixed engine list iteration code so it uses ENGINE_free() to release

       structural references.

     - Constified the RAND_METHOD element of ENGINE structures.

     - Constified various get/set functions as appropriate and added

       missing functions (including a catch-all ENGINE_cpy that duplicates

       all ENGINE values onto a new ENGINE except reference counts/state).

     - Removed NULL parameter checks in get/set functions. Setting a method

       or function to NULL is a way of cancelling out a previously set

       value.  Passing a NULL ENGINE parameter is just plain stupid anyway

       and doesn't justify the extra error symbols and code.

     - Deprecate the ENGINE_FLAGS_MALLOCED define and move the area for

       flags from engine_int.h to engine.h.

     - Changed prototypes for ENGINE handler functions (init(), finish(),

       ctrl(), key-load functions, etc) to take an (ENGINE*) parameter.

     [Geoff]

  *) Move 'if (!initialized) RAND_poll()' into regions protected by

     CRYPTO_LOCK_RAND.  This is not strictly necessary, but avoids

     having multiple threads call RAND_poll() concurrently.