Because of spacing issues in the right sidebar, the unread counts
appear to the left of the person's name, not the right.
It's kinda awesome that this is only 20 lines of code.
(imported from commit f5a4ea27bc4cd2e8157746ce7524a600b638930b)
Most of the model logic pertaining to unread counts had been in
zephyr.js, along with a couple global variables. Now the code
is encapsulated in unread.js. It was a pretty straightforward
extraction with some minor method name changes. Also, a small
bit of the logic had also been in stream_list.js.
Conflicts:
tools/jslint/check-all.js
(imported from commit f0abdd48f26ab20c5beaef203479eb5a70dacfff)
