Tests: refactor tests

We need to simplify a bit our tests.
Also, we need to mark as `@Ignore` tests as they break now due to some cluster controls after each test in elasticsearch test infra.

See [org.elasticsearch.test.ElasticsearchIntegrationTest#ensureClusterSizeConsistency()](https://github.com/elasticsearch/elasticsearch/blob/v1.3.1/src/test/java/org/elasticsearch/test/ElasticsearchIntegrationTest.java#L974-L979)

Closes #33.
Add multiple zones support

Closes #27.