Prior to this change, `go test -count=2 ./models` would fail like:
--- FAIL: TestMarshal (0.00s)
points_test.go:37: got: ,A\ FOO=bar,APPLE=orange,host=serverA,region=uswest
points_test.go:38: exp: ,apple=orange,foo=bar,host=serverA,region=uswest
points_test.go:39: invalid match
because a later test reassigned the package-level variable that
TestMarshal depends on. Don't reassign that variable anymore.
Also cleaned up some whitespace, and moved an init function to the top
of the file for visibility.