Merge pull request #1 from anna-khokhlova/vboronin.branch.AkkaTest

added integration test inside of AkkaClusterTest module
Sender now sends HELLO message periodically to all receivers.
Signed-off-by: Anna Khokhlova <->
Added handling of reachable/unreachable events
Signed-off-by: Anna Khokhlova <->
Merge pull request #2 from anna-khokhlova/anna.test.branch

Sender now sends HELLO message periodically to all receivers.
Update README.md