Fixed ObservableReleasesClient.GetAssets

to use the correct url.
Fixing some unit tests that were not doing

any assertions.
Adding Received() where it was missing.
The majority of these instances were unawaited AssertEx.Throws
They are now all either awaited or replaced with Assert.Throw
Assert.Throw was used when possible and when not an option
AssertEx.Throw was awaited.
Merge branch 'bad_assets_url' into nonfunctioning_tests
Merge branch 'master' of https://github.com/octokit/octokit.net into nonfunctioning_tests
Fixing AuthorizationsClientTests.

TheGetOrCreateApplicationAuthenticationMethod.WrapsTwoFactorFailureWi...
thTwoFactorException while I'm in here.
renamed IObservableBlobClient to IObservableBlobsClient
added marker interfaces for missing clients
renamed properties on IObservableActivitiesClient
renamed method on IObservableWatchedClient
corrected overload name to be consistent
corrected parameters on IObservableSearchClient
renamed property on IObservableOrganizationTeamsClient
IObservableOrgaizationTeamsClient -> IObservableTeamsClient
fix them projects
suppressing fire!
renamed name -> repo
interfaces do not require property setters
implemented missing method on IObservableIssueCommentsClient
added missing properties to IObservableIssuesClient
updated properties on IObservableGitHubClient