Garbage collect networks after test completion

Signed-off-by: Eli Skeggs <eskeggs@globesherpa.com>
[0.3.3] add tests, fix $spark trust issue

A couple of the tests were too over the top for a single process, and
would max out the allowed file descriptors, so they had to be trimmed
down.

The spark handler would trust the seeds just like $find prior to
e6815ed. Now the spark handler just seeds with the provided node info
instead of adding the node directly, ensuring no desynchronicity issues
with adding a node after the node has been destroyed.

Signed-off-by: Eli Skeggs <eskeggs@globesherpa.com>