Spec\acceptance test with ScalaTest+Gradle

This is an experiment on solving #1 using Gradle+Ivy+ScalaTest for build\deps mngt\Tests

- [x] setup infra: gradle wrapper, project structure, build script, test wrapper
- [ ] write actual test logic


Pro:
 - only 1 per-reuqest: jvm (binary packages exist for most OS)
 - [flexible](http://scalatest.org/user_guide/selecting_a_style) test style

Con:
 - Ugly dir structure
 - less elegant then https://github.com/nytlabs/hive/blob/master/spec/