Make an (overdue) note about the recent ENGINE restructuring. Apart from

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

         +) applies to 0.9.7 only

  +) Major restructuring to the underlying ENGINE code. This includes

     reduction of linker bloat, separation of pure "ENGINE" manipulation

     (initialisation, etc) from functionality dealing with implementations

     of specific crypto iterfaces. This change also introduces integrated

     support for symmetric ciphers and digest implementations - so ENGINEs

     can now accelerate these by providing EVP_CIPHER and EVP_MD

     implementations of their own. This is detailed in crypto/engine/README

     as it couldn't be adequately described here. However, there are a few

     API changes worth noting - some RSA, DSA, DH, and RAND functions that

     were changed in the original introduction of ENGINE code have now

     reverted back - the hooking from this code to ENGINE is now a good

     deal more passive and at run-time, operations deal directly with

     RSA_METHODs, DSA_METHODs (etc) as they did before, rather than

     dereferencing through an ENGINE pointer any more. Also, the ENGINE

     functions dealing with BN_MOD_EXP[_CRT] handlers have been removed -

     they were not being used by the framework as there is no concept of a

     BIGNUM_METHOD and they could not be generalised to the new

     'ENGINE_TABLE' mechanism that underlies the new code. Similarly,

     ENGINE_cpy() has been removed as it cannot be consistently defined in

     the new code.

     [Geoff Thorpe]

  +) Change ASN1_GENERALIZEDTIME_check() to allow fractional seconds.

     [Steve Henson]