Deleted orphaned .meta files

Asset files ShowProducts and ShowUnityInput were deleted from the
project hierarchy in a previous commit. Clearing out the related
leftover .meta files.
Cleaned up obsolete usage debug warnings

Using SetActive() or .activeInHierarchy instead of the .active property
on game objects. Now referencing main camera using Camera.main instead
of Camera.mainCamera. Updated BoxCollider.extents property reference to
BoxCollider.bounds.extents instead.