added "delete" function
* that is, edded, documented, tested
* used functions getRequired* and removed extra ";"
* put hk1.7 everywhere
Merge branch 'adddelete' of github.com:sorin-costea/vertx-mod-elasticsearch into sorin-costea-adddelete

Conflicts:
	src/test/java/com/englishtown/vertx/elasticsearch/integration/IntegrationTest.java
Merge branch 'sorin-costea-adddelete' into develop