Overhauled the Perl interface (perl/*):

- ported BN stuff to OpenSSL's different BN library

- made the perl/ source tree CVS-aware

- renamed the package from SSLeay to OpenSSL (the files still contain
  their history because I've copied them in the repository)

- removed obsolete files (the test scripts will be replaced
  by better Test::Harness variants in the future)