Reconstruction snapshots now include pose and calibration packets, so
that they can actually be reconstructed. Recording options in the
configuration have also been moved from the root to controls.

2D snapshots now have alpha blending between the channels.
3D snapshots have been added, though the feature is not yet functional.
Recording window for detailed options has been added, though it is still
missing most functionality.

This reverts commit 55795d67.