This change makes three updates to our test configuration.
First, --pyargs has been removed so that the test runner command-line

uses the standard pytest syntax for selecting tests (filesystem paths +

::ClassName::function_name). We had put this in to try to maintain

compatibility with the old nose test runner, but the syntax was already

slightly different (nose used :ClassName.function_name) and this makes

it easy to copy/paste a test name from the failure list into a new

command line.
Second, this updates the list of suppressed warnings further to remove

things which are no longer problematic, and add a couple things that I

don't want to deal with right now.
Last, the test capture glob has been updated to be more correct. This

doesn't seem to affect the total number of collected tests, but might

in the future.

Ran unit tests.