Fix and improve intergration tests

Merge branch '0.2'

Bump ramsey/uuid version (#8)

Reset client ID to default one when device ID is empty

Fix 'Call to a member function close() on null' error

Fix PHP 7.2 compatibility (#6)

Vendor patched React MQTT Client classes

See binsoul/net-mqtt-client-react#17 and
binsoul/net-mqtt#8 for clarification.

Cancel connection attempt on timeout

Tighten constraint for binsoul/net-mqtt version

Add Lite::isConnected() method