True first release of the prototype

Many changes since last release. Mostly internal refinements / reworks. Two new features users will notice:

1. Vastly improved output JSON. Now syntactically correct except that string values aren't quoted properly.
2. Unicode support for both column names and CSV file contents. Bring on the emojis!

Bug fixes, function name change, removed extracted_bit_stream requirement

main is now called generate_pdep_stream. You no longer need to pass an extracted_bit_stream argument to generate_pdep_stream, as you used to with main. Here's the signature for the new function:

generate_pdep_stream(field_width_stream_wrapper, idx_marker_stream_wrapper, pack_size,
target_format, csv_column_names)

This release also adds lot of new unit tests, and improves the documentation for many key functions.

Initial release of middle-third of the CSV to JSON transducer prototype

Principle development of the middle third of the transducer is complete. To use the transducer, the user supplies the following arguments to the main function in pdep_marker_stream_gen.py:

main(extracted_bits_stream, pext_marker_stream, idx_marker_stream, pack_size, target_format, csv_column_names)