CLI: Set-up automated testing & specs

[FokkeZB]

Some ideas:

• Add a special namespace to the registry that returns what you ask for:
  • registry.gitt.io/widget-foo-1.3.1-nodist
• Create a fake project with tiapp.xml and config.json
• Add a way to have gittio use a fake "global path" for modules while testing
• Writes specs for all scenarios, specially combinations of -g, out/inside a project and older/newer/undefined versions