Match IR and depth frames based on their timestamps

[papr]

• [x] Test Python access to the original data's timestamps
• [x] Test if IR and depth images have matching timestamps, i.e. check if the same timestamp occurs in IR and depth data.
• [x] Only create FramePairs for IR/depth frames with matching timestamps
• [ ] Think about not overwriting the original timestamps with g_pool.get_timestamp()
  • [ ] Check the timestamp's time epoch
  • [ ] Sync Pupil time (g_pool.timebase) such that it matches the Picoflexx time epoch

We would appreciate it very much if you could work on this issue, @Murnto.