* lib/rupnp/build_url.rb renamed to lib/rupnp/tools.rb.

* lib/rupnp/tools.rb: add #snake_case method to transform a
  camel cased string to snake cased one.

* lib/rupnp/base.rb: require tools instead of build_rul

* lib/rupnp/service.rb: use snake_case instead of home made
  transformation in #define_method_from_action.
* lib/rupnp/constants.rb: correct HOST_IP. No more handle a
  AddrInfo but a string with IP address
* lib/rupnp/device.rb:
  - correct device creation: wiat for all devices and services'
    creation before assert succeed.
  - create methods from service type to retrieve then easily
* lib/rupnp/service.rb: correct SOAP message sending
* lib/rupnp/constants.rb: freeze constants

* lib/rupnp/service.rb: define methods from actions : OK