Adding matrix conversion for debug.
Merge pull request #19 from googlesamples/feature/v2.0_video_overlay_example

Feature/v2.0 video overlay example
Change the colour to red.
Adding Event Output and Library Version.
Timestamp to delta time.
Unifying the UI and third person camera position.
Merge branch 'master' of https://github.com/googlesamples/tango-examples-c.
Stop tracking unnecessary files, update gitignore.
- fit in tango-gl-structure.