Add "spring test app.groovy test.groovy" to CLI

Add ability to run "spring test app.groovy test.groovy" and have it find and run all @Test cases
- Compile all the groovy files
- Find any classes that have @Test methods, and run them through JUnit
- Create various integration tests to confirm behavior
- Add autoconfiguration to CLI so that it adds @Grab(junit) as well as key import statements to simplify for user