Hazelcast3 support including dist files and integration tests

Hazelcast3 support including dist files and integration tests.

Hazelcast 3.2 has some critical bug fixes in it.

To use Hazelcast 3.2 with vertx use the distribution file called:

vert.x.hazel3cluster-${version}.zip or
vert.x.hazel3cluster-${version}.tar.gz.

A new gradle jar project was created called 'vertx-hazelcast3'. Vertx
uses a service location pattern to load the in a pluggable cluster
manager. This fix employs the pluggable nature of vertx cluster manager
to plugin Hazelcast 3 instead of Hazelcast 2.

This produces a new jar file that has a new cluster manager factory
which can be loaded with the service locator.

It has been tested.

Find more details at:

https://github.com/RichardHightower/vert.x/wiki/Using-Hazelcast-3.2
Hazelcast3 support. Renamed SPI classes to avoid conflicts.

Reamed SPI for Hazelcast3 factory to avoid conflicts. Put them in a
hazelcast3 package and named the main interfaces Hazelcast3* instead of
Hazelcast.