Remove automatic addition of test spies

This brings the test suite down to just over half a second versus almost a minute with enough CPU utilization to get my MacBook Pro's fans spinning. @katowulf I'd like to get this out ASAP as 0.4 and then consider whether there needs to be some special facility for attaching spies to child references in the future. I'll also jump over to AngularFire and write up a PR updating the tests for 0.4 that can be merged after release.

Closes #26