Implemented DeploymentsClient and unit tests
Implemented DeploymentStatusesClient and unit tests
Initial simple integration tests for DeploymentsClient

Just checking that we get something back when creating a deployment
and that we can get deployments from a repository that is known to have
them.
Initial integration tests for DeploymentStatusClient
Added documentation comments to...

IDeploymentsClient and IDeploymentStatusesClient and related request/
response classes.
Changing DateTime to DateTimeOffset...

because it's what it should have been all along.
Renamed GitDeployment to Deployment
Added second integration test for DeploymentStatuses..

and cleaned up Integration/DeploymentClientTests.cs some.
ApiUrls documentation comments
Added documentation comment remarks with links...

to api documentation for methods.
Added deserialization unit test for Deployment

Not sure it needs a serialization one since the client should never have
to serialize them
Implemented deserialization unit test for...

DeploymentStatus as well.
These are technically already covered with the integration tests but
this way they can be run without running the integration tests.
Merge branch 'master' into deployments_client
Merge remote-tracking branch 'upstream/master' into deployments_client
Implemented ObservableDeploymentsClient and...

unit tests.
Implemented ObservableDeploymentStatusClient and...

unit tests.
Formatting
Merge branch 'master' into deployments_client
Fixing argument tests for ObservableDeployments...

Client and ObservableDeploymentStatusClient. Needed to make sure that
the tasks were actually run and not just scheduled.
reworking CONTRIBUTING to be more than bullet points