Fix possible bugs with list options: avoid too early deallocations, check for embedded NUL characters, make curl_formadd() 64-bit clean.
Fix possible bugs with list options: avoid too early deallocations, check for
embedded NUL characters, make curl_formadd() 64-bit clean.

ashumkin/pycurl-cvs,ashumkin/pycurl-cvs,ashumkin/pycurl-cvs