remove the PORTDELTA configuration

This option was used to increment all listening ports by a constant...
xivo-ctid configuration will now be in xivo_cti.config

the config will have a dict like interface
move bus configuration to the default_config dict
add a ChainMap class to order configuration dicts
move all cli options to the xivo_cti.config "dict"
move CTI_PROTOCOL_VERSION to xivo_cti.__init__

this is a constant, not really a config option
move DAEMONNAME to xivo_cti.__init__
move BUFSIZE_LARGE  to xivo_cti.__init__
remove unused constant XIVOIP
move the DB_URI to xivo_cti.config["db_uri"]
move the SSLPROTO constant to xivo_cti.__init__
move ALPHANUMS to xivo_cti.__init__
the ctid configuration is now contained in a dict like object in xivo_cti.config

all accessors and mocks are modified to use the new config dict. A unittest that
did not test context separation correctly was removed in test_meetme_service_notifier

Live configuration update is now "disabled"
make the configuration updatable
Wrap the configuration in a UserDict to be able to modify the dict after an import

remove some helper methods in the ChainMap that were not available in the python 3
implementation.
use the dird section of the configuration to launch the dird client
add a configuration file to xivo-ctid
remove the unused parameter key from the db config object in cti_config
add pyaml to the requirements.txt file
move ChainMap from xivo_cti.cti_config to xivo.chain_map