Update BufferedPatchDataset

[counkomol]

There are several issues with BufferedPatchDataset (bpds) that need to be addressed:

• It is currently not covered by a test.
• The buffer_switch_frequency parameter is confusing. The parameter value is used as an interval/period, not a frequency.
• The npatches parameter is arbitrary. A bpds object really has no "length" in the traditional sense.
• It uses a standard Python list to implement a queue, which is sub-optimal.
• It is a subclass of FnetDataset, yet does not use the underlying methods/attributes of FnetDataset.
• It is not truly a dataset:
  • It's __len__ is meaningless as mentioned above.
  • It's __getitem__ is random.
• There is a bug where the first buffer swap occurs too early.
• The documentation generally needs to be improved.
• The public attribute self.remaining_to_be_in_buffer is unused and misleading when shuffle_images is set to False.

[gregjohnso]

Closing issue as it is marked as done