Device tracker calls callback instead of sockets
Update for JsMessage API
Tests pass on all platforms with and without phone
Tests pass if ADB is open in the background
Set worker to null on reset
Merge pull request #775 from bkase/adb-tests-fix

ADB `make test` fixes. Fixes #760
Merge pull request #755 from bkase/device-tracker-js

 Device tracker calls callback instead of sockets