Add iterators for streams, provide .iter on device list

[wolfd]

This slightly reworks the DeviceList iterator, but not much.

Topic: stream-iterators

[wolfd]

Reviews in this chain:
└#6 Add iterators for streams, provide .iter on device list

[wolfd]

#	head	base	diff	date	summary
0	d90ee834	d28b0aad	diff	Mar 4 0:27 AM	3 files changed, 96 insertions(+), 25 deletions(-)

[wolfd]

Closing in favor of #1