like Malloc, Realloc and especially Free conflict with already existing names
on some operating systems or other packages. That is reason enough to change
the names of the OpenSSL memory allocation macros to something that has a
better chance of being unique, like prepending them with OPENSSL_.
This change includes all the name changes needed throughout all C files.
new DSA public key functions that were missing.
Also beginning of a cache for X509_EXTENSION structures: this will allow them
to be accessed more quickly for things like certificate chain verification...
