Fix strong-remoting tests

Copy test-server files from strong-remoting-android to
test-server/remoting.

Move specification of dependencies from test-server/package.json to the
top-level package.json file.

Enhance the test server to log requests issued by the tests, this makes
it easier to troubleshoot failing tests.
test-server: fix setup of push-notification
test-server: rework auth setup to 2.0 style
UserRepository: fix `logout` to use `POST` method
build.gradle: log more info
build.gradle: update to Android 5.0 (API 21)

 - Upgrade Android Build tools to 21.0.2
 - Upgrade Target SDK Version to 21
Merge pull request #47 from strongloop/fix/failing-tests

Fix failing tests