The new list_cursor class is more generic and saves the state
of your cursor across redraws.
Note that we no longer cycle from bottom to top or vice versa.
The node test code that was removed here was kind of complex
and didn't actually assert useful things after calling methods.
If you typed in more than one word for a stream with multiple words in
it's name, it would not show up in the search list. This fixes that
and adds some more tests covering the entire functionality of the
filter.
Added new file to test stream sort. Specifically,
it tests the `sort_group` function's ability to put
streams into the corect pinned/normal/dormant category,
filter them based on keyword, and sort alphabetically.
