In memory support for openssl_pkcs7_*

Hi, The PHP functions openssl_pkcs7_(sign|encrypt|decrypt|verify) do require files to be executed. In many cases this will create the unintended requirement of temporary files. In compare with openssl_(sign|encrypt|decrypt|verify|...) which are doing almost the same thing this is a strange behavior. When we look at the purpose of openssl_pkcs7_* (working with digital signatures in mail), you would not expect to work with files instead of strings for this few data. Regards, Paul