Common targets are:
  - meta-agl:          (core system)
    agl-image-minimal
    agl-image-minimal-qa
    
    agl-image-ivi
    agl-image-ivi-qa
    agl-image-ivi-crosssdk
    
    agl-image-weston

  - meta-agl-demo:     (demo with UI)
    agl-demo-platform  (* default demo target)
    agl-demo-platform-qa
    agl-demo-platform-crosssdk
    
    agl-demo-platform-html5