added uaPrestogres and uaPrestogresExternal UserAuth types
pgpool2: added presto_server and presto_catalog config options
implementing prestogres_md5 and prestogres_external
export send_md5auth_request and read_password_packet
implemented prestogres_md5 authentication mechanism
implemented prestogres_external authentication mechanism
enable hba by default
added comments and examples to pool_hba.conf and pgpool.conf
added 'prestogres passwd' subcommand
updated README.md
changed 'prog' option to 'auth_prog' to be consistent with pgpool.conf
prestogres subcommands require -D option
updated README.md
added --with-openssl to ./configure of pgpool2
updated README.md
updated README.md
fixed pgpool.conf to use ' to quote strings
updated README.md
updated README.md