This matches the OpenXR usage: the array is the plural of the element type,
and the count is the singular element type plus "count" (usually CountOutput
because of the two-call idiom)
Includes fixes to other code to match API changes.
Invalid poses may be handled more gracefully in the future. For now poses
are not transformed if orientation is not valid, because transforming with
an invalid quaternion will have bad results in any way.
v2: Upgrade poses with valid position but invalid orientation to valid poses