Hololens context loss + recreation loses holographic cameras

[mlfarrell]

This one took quite a few beers and staying up til 2am last night to figure out. My patch for it is below, I'm sure your official solution will be more graceful:

mlfarrell@a1795af

[austinkinross]

@MikeRiches - fyi

[mlfarrell]

@MikeRiches expanding upon this. The loss of a holographic camera (but not the context) causes false positive errors due to a lack of mapping between camera ids and holographic poses. I potentially fixed that issue here with this commit:

mlfarrell@ce1a9ca