Removed networking from lxc type.

* From now on first network interface will have to be configured using
  lxc_interface thus avoiding duplication of functionalities because for
  having a real networking configuration all parameters/properties from
  lxc_interface should be duplicated on lxc for just configuring the
  first device.
Allow to configure first interface.

* Modified regex so index can be 0.
* Added device_name property so title can be whatever user finds
  suitable.
* Added tests for device_name property, including getter/setter.
* Added tests to verify index 0 is allowed.
* Added basic acceptance test to verify lxc_interface.
* These changes are not backwards compatible, so version will bump to
  1.0.0.