Allow for batches of blocks to be post-processed

[0237h]

Problem

Currently, all blocks need to be processed before passing onto the post-processing step (just stored into a file as of now, see #11).
This makes it unconvenient when working with large block ranges or with a lot of data that needs to be stored in memory.

Also, if an unexpected error occurs at the block processing step, all previously processed block data will be lost and nothing will be available in the final output.

Proposition

Allow for having batches of processed blocks (customizable) to be sent to the post-processing step.