[server] Improve MySQL db config.

    * Allow password with special characters;
    * Accept port configuration;
    * Allow using ssl connection.

    Example:
    [database]
    ENGINE = mysql
    HOST = 127.0.0.1
    PORT = 3306
    USER = seafile
    PASSWD = P@$$word
    DB = seafile-db
    USE_SSL = True
update ccnet version to 1.3.6
add strtok_r for windows