Introducing new "protocols" option for master config

This option allow to configure protocol specific parameters(such as port) for different slave types. It replaces "slavePortnum" option in config, but keeping backward compatability as well.

Format:
c['protocols'] = {'proto': {'option1': 'value1', 'option2': 'value2'}, ....}

slavePortnum = 9999 will matches c['protocols'] = {'pb': {'port': 'tcp:9999'}}