* lib/rupnp.rb: add require for rupnp/device.rb

* lib/rupnp/device.rb: correct "typos".

* lib/rupnp/ssdp.rb: correct typos.

* lib/rupnp/ssdp/http.rb: in #get_http_verb, correct regex to
  handle first HTTP line.

* lib/rupnp/ssdp/notifier.rb:
  - correct typos.
  - add port on LOCATION lines in notifications

* lib/rupnp/ssdp/search_responder.rb:
  - include SSDP::HTTP.
  - do nothing if a NOTIFY is received.
* lib/rupnp/control_point.rb:
  - include RUPNP::Tools.
  - when accessing notification hash, use string keys instead of
    symbol keys (in #search_devices_and_listen).
  - in #search_devices_and_listen: retrieve UDN from USN as UDN is
    not sent in NOTIFY message.

* lib/rupnp/cp/base.rb: typo corrected.

* lib/rupnp/cp/remote_service.rb:
  doc: correction for Action documentation.

* lib/rupnp/ssdp/listener.rb:
  - include SSDP::HTTP.
  - in #receive, for 1st log, change ' by ".
  - typos corrected.

* lib/rupnp/tools.rb: add #usn2dn method.