Make notes about ENGINE changes.

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

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

         +) applies to 0.9.7 only

         +) applies to 0.9.7 only

  +) Add "ex_data" support to ENGINE so implementations can add state at a

     per-structure level rather than having to store it globally.

     [Geoff]

  +) Make it possible for ENGINE structures to be copied when retrieved by

     ENGINE_by_id() if the ENGINE specifies a new flag: ENGINE_FLAGS_BY_ID_COPY.

     This causes the "original" ENGINE structure to act like a template,

     analogous to the RSA vs. RSA_METHOD type of separation. Because of this

     operational state can be localised to each ENGINE structure, despite the

     fact they all share the same "methods". New ENGINE structures returned in

     this case have no functional references and the return value is the single

     structural reference. This matches the single structural reference returned

     by ENGINE_by_id() normally, when it is incremented on the pre-existing

     ENGINE structure.

     [Geoff]

  +) Fix various bugs related to DSA S/MIME verification. Handle missing

  +) Fix various bugs related to DSA S/MIME verification. Handle missing

     parameters in DSA public key structures and return an error in the

     parameters in DSA public key structures and return an error in the

     DSA routines if parameters are absent.

     DSA routines if parameters are absent.