Allow using gpg passphrase in the command line

Updated to allow the addition of --encryption-passphrase to override the config gpg_passphrase setting.
Added option
Added check to see if the option is there and has value - update the cfg if appropriate
Updated the args in gpg_decrypt and gpg_encrypt to include the pass phrase from the singleton Config

usage;

s3cmd -e --encryption-passphrase 2asr3F3fdd324 put [FILE] s3://.....