CloudRequestEngine fails to construct if cloud.51degrees.com is unavailable

[romansertsov]

fix for #62

[justadreamer]

The change is good, however in a real Pipeline the CloudEngine will be used. It nests the CloudRequestEngine.

CloudEngine eagerly requests these properties of cloudRequestEngine in its ctor.

You need to make the CloudEngine.ready() method to call CloudRequestEngine.ready() method, and remove the CloudEngine.ready() method call from its constructor. Then it will trigger loading of the properties lazily only when it is doing processing by triggering its ready() method which in turn should check if CloudRequestEngine() is ready().

[justadreamer]

could you please add a test of the whole Pipeline that is constructed sort of like in cloud/gettingstarted-web example and flowData.process() method is called with a mocked properties request and then we check that no failures happen during construction, but processing fails with the expected error that it could not load the cloudProperties or evidenceKeys...