• Default all missing fields to None instead of 0 or "" so we can check whether there actually is a value assigned if necessary.

• Finished support for generating frames directly from PDF slides (closes #8). ...

• Specified defaults for audio and video stream numbers.
• Fixed some typos on comments and debug output.
• Added "/" as a valid filename character for config files.
• Added some comments explaining the more obscure class variables in the Segment class.
• Generalised Segment.generate_last_frame() into generate_frame().
• Ensured that generate_temp_file() returns the generated filename.

• Moved segment classes into separate module (closes #7). ...

• Moved global configuration into separate module.
• Made format of debug logging more consistent.
• Added a few more info logging messages.
• Renamed configuration parser module.