Fix .asd
Fix .asd

Fixed license reference in asd file to refer to readme.html, which is
a verbatim copy of CFFI's license.

dkochmanski/cffi,3b/cffi,3b/cffi,stassats/cffi,dkochmanski/cffi,attila-lendvai/cffi,3b/cffi,stassats/cffi,mcna/cffi,attila-lendvai/cffi,cffi/cffi,dkochmanski/cffi,stassats/cffi,cffi/cffi,mcna/cffi,cffi/cffi