Introducing space-shooter plugin

Welcome, space traveler!

This plugin is part of UI Plugins Crash Course:

  http://www.ovirt.org/Tutorial/UIPlugins/CrashCourse

This plugin contains Alien Invasion, sample HTML5 game
developed by Pascal Rettig and released under both GPL
and MIT license:

  https://github.com/cykod/AlienInvasion

Refer to Crash Course wiki for step-by-step tutorial.

Check out README file for details on installation.

Change-Id: I347b18ca57b7b41e4cdf42e528cf5a7aff60c583
Signed-off-by: Vojtech Szocs <vszocs@redhat.com>