Update the info on version numbering

=head1 NAME

OPENSSL_VERSION_NUMBER, SSLeay - get OpenSSL version number

OPENSSL_VERSION_NUMBER, SSLeay SSLeay_version - get OpenSSL version number

=head1 SYNOPSIS

 #include <openssl/crypto.h>

 long SSLeay(void);

 char *SSLeay_version(int t);

=head1 DESCRIPTION

OPENSSL_VERSION_NUMBER is a numeric release version identifier:

 MMNNFFPPS: major minor fix patch status

The status nibble has one of the values 0 for development, 1 to e for betas

1 to 14, and f for release.

for example

 0x000906000 == 0.9.6 dev

 0x000906023 == 0.9.6b beta 3

 0x00090605f == 0.9.6e release

Versions prior to 0.9.3 have identifiers E<lt> 0x0930.

Versions between 0.9.3 and 0.9.5 had a version identifier with this

interpretation:

 MMNNFFRBB major minor fix final beta/patch

for example

 0x000904100 == 0.9.4 release

 0x000905000 == 0.9.5 dev

Versions prior to 0.9.3 have identifiers E<lt> 0x0930.

Version 0.9.5a had an interrim interpretation that is like the current one,

except the patch level got the highest bit set, to keep continuity.  The

number was therefore 0x0090581f.

For backward compatibility, SSLEAY_VERSION_NUMBER is also defined.

SSLeay() returns this number. The return value can be compared to the

macro to make sure that the correct version of the library has been

loaded, especially when using DLLs on Windows systems.

SSLeay_version() returns different strings depending on B<t>:

=over 4

=item SSLEAY_VERSION

The text variant of the version number and the release date.  For example,

"OpenSSL 0.9.5a 1 Apr 2000".

=item SSLEAY_CFLAGS

The flags given to the C compiler when compiling OpenSSL are returned in a

string.

=item SSLEAY_PLATFORM

The platform name used when OpenSSL was configured is returned.

=back

If the data request isn't available, a text saying that the information is

not available is returned.

For an unknown B<t>, the text "not available" is returned.

=head1 RETURN VALUE

The version number.