Added KinnectFusion bilateral filter (edge-preserving, noise reduction filter).

[jbaileyhandle]

Also added floating-point function to round to xth sfd bit (useful for FP testing where non-associativity / non-transitivity of operations can cause very slight differences between actual and reference results). Added signed int min/max functions and clamp function.

[cdleary]

This was stalled to the point it requires some rebasing now -- if you rebase I can merge it promptly. Really sorry about the delay!

[hongted]

@meheff -- let me know if you'd like to request additional changes. Otherwise, I can start the process of merging this.

[vincent-mirian-google]

There is conflict with base. When resolved, I am open to help merge this.

[jbaileyhandle]

Unless anyone objects, I'm inclined to close this PR for the moment without integrating into the main branch. If I recall, I tried to rebase back in November (?) and discovered that there were some unresolved issues in the test data that would take some time to resolve.

[vincent-mirian-google]

Thanks for the reply @jbaileyhandle.

I don't have any objections. If @hongted @meheff @cdleary don't have any objections, we can close the PR. Best.