Fixed bug in output from parser test.

Added a development virtualenv and documented requirements.

Replaced import * with explicit name imports.

Fixed logging of SegmentError (renamed to follow conventions) — ref #32.

Fixed use of itertools.count() to generate segment numbers (ref #32).

Changed distutils.spawn.fine_executable() to shutil.which() (ref #32).

Converted os.path to pathlib and all #! lines to python3 (ref #32).

Converted all print statements to functions for Python 3 (ref #32).

Merge branch 'master' of https://github.com/nstanger/process_podcast

• Added Visual Studio Code workspace.

• Added --copy-audio and --copy-video options to disable all additional stream processing (reducing audio channels, etc.). ...

• Removed -n for --no-normalise.
• Added configurable audio and video codecs via --audio-codec and --video-codec options.
• Fixed bug where the final punch out time for an odd number of timestamps was incorrectly calculated.

• Added --no-normalise option to disable normalisation of the source audio.

• Rewrote shellquote() to ignore things like command-line switched and executable paths. Also only execute the catch-all regex when no other regexes match (closes #27). ...

• Switched to double-quoting of strings because that makes it easier to handle single quotes in strings (which is more likely than double quotes).
• Added more test cases.

• Updated regular expressions in ShellCommand.shellquote() to catch the weirder edge cases (closes #26).

Merge branch 'master' of https://github.com/nstanger/process_podcast

• Added --preview option (closes #17).

• Now checks whether a filename already starts with the input prefix before adding it (closes #25).

• Ignored .pyc files.

• Minor formatting change.

• Added basic README file.

• Added example of inserting an annotated PDF slide into the video stream.

• Deleted leftover development debugging output. ...

• Added code to resize frame inputs to the size of the smallest video segment where applicable (closes #23). Still need to add resizing for differently sized video inputs.

• Redesigned FFprobeCommand to retrieve media file entries in JSON format for easier extraction and processing. ...

• Changed default of --input-prefix to “.”.
• Added check that the input prefix actually exists.
• Ensured that the segments list variable actually exists when cleanup happens.

• Ensured that prefix isn’t added if input filename is “^”. ...

• Rearranged display of frame processing progress bar.
• Better handling of frame segment processing errors:
    – Added SegmentException.
    – Checked all subprocess exit status values.
• Moved cleanup() call into finally clause.
• Added Segment._temp_files_list to make deletion of temporary files more predictable, and eliminate inadvertent deletion of original source files for PDF frame inputs.
• Refactored segment temporary file generation (closes #22).

Merge branch 'master' of https://github.com/Otago-InfoSci-Database/Tools

• Ensured progress bar is silent when maximum value is zero.

• Added debug code to output number of frame segments.

• Rewrote get_configuration() to fix a crasher when processing frame inputs. Also refactored to eliminate duplicate code. ...

• Defaulted args.prefix to "".
• Renamed some variables.
• Added some documentation and debugging calls.

• Added --input-prefix option (closes #13). ...

• Fixed an undiscovered bug in process_timestamp_pair() that would have caused a crash when there was an odd number of timestamps (failed to check whether second timestamp is defined).

Merge branch 'master' of https://github.com/Otago-InfoSci-Database/Tools