task/ta-npi-016-20 -- add support for conditional SMS

nparcel/conf/nparceld.conf
* deprecate the SMS special facility
* add placeholder for new option "sms_scheme" in the rest section

nparcel/config.py
* deprecate support for special email and sms facilities

nparcel/emailer.py
* tweak the initialisation of the _sender attribute

nparcel/loader.py
* patch bug with the Smser object initialisation

nparcel/loaderdaemon.py
* deprecate support for special sms facilities
* provide required SMS initialisation argument to Loader() call

nparcel/smser.py
* refactor the send() method to provide some number validation