nsqd: improved test logging
test: don't run with -v
nsqd: remove assert test dependency
deps: bump go-snappystream to v0.2.0
nsqd: explicitly clean up test connections

this ensures that the connections are referenced until the end
of each test function execution, to prevent a pre-emptive GC
from cleaning up and closing a connection underneath.
deps: remove assert/pretty/text
nsqlookupd: improved testing logging
nsqlookupd: remove assert dependency
pqueue: remove assert dependency