renamed getDescription methods to describe*
JUnit runner refactored to extend JUnit ParentRunner, added support for annotations

The following annotations are supported:
- Setup: called before looking up the es cluster and parsing the test suites. Useful to start es cluster if needed. Annotated methods need to be static with no arguments.
- BeforeAllTests & AfterAllTests: to do something at the beginning of the suite, or at its end. Annotated methods need to be static and require the execution context as argument
- BeforeTestSection & AfterTestSection: to execute code before or after each test section. The annotated methods need to be static and need to have the execution context as argument

Moved teardown method out of the runner and implemented as a @BeforeTestSection method in the test class, as well as a @AfterAllTests to clean everything up at the very end
Moved junit runner and junit classes to junit package
Moved RestTestSuite to test.section package
Moved junit runner and junit classes to junit package
Moved RestTestSuite to test.section package
added elasticsearch-test dependency and automatically started test cluster through @Setup annotation