Link in Readme no longer resolves

[AcomaChris]

Repro

1. Go to the Readme.md
2. Attempt to resolve the following link in the Readme.md
   --- http://secondreality.co.uk/blog/how-to-create-mixed-reality-videos-for-the-vive-with-two-controllers/
3. Observe result

Result
That link 502's now.
http://secondreality.co.uk/blog/how-to-create-mixed-reality-videos-for-the-vive-with-two-controllers/

Expected Result
Link with instructions for mixed reality should resolve to an appropriate webpage.