Metadata for cycled recording

[leewujung]

• [x] Add duty cycle on/off time to metadata within each AIFF files (see #13)

[aidanjohnson]

Just need to check all is correct.

UPDATE (2018-07-13T12:00): Checked with Audacity that the sunset and sunrise time (in Unix Epoch) is set as the author (artist) metadata--I think my belief that it was not properly being set was a false start (ugh..wasted time). We can easily change the field in which the metadata is saved, as well as add more metadata (see #13). There are the following fields available:

• Name (AIFF_NAME)
• Author (AIFF_AUTH)
• Copyright (AIFF_COPY)
• Annotations (AIFF_ANNO)