Those naughty MethodMissingExceptions

So we had some compatibility shims inside Octokit for moving to .NET 4.5.

And then we moved to .NET 4.5 and forgot to delete them! Oops.

![](http://i.imgur.com/YQm4f.gif)

This fixes that.

@Haacked I'm seeing some unrelated tests fail on my machine. Can you repro?

**Octokit.Tests.Exceptions.ApiExceptionTests+TheConstructor.CanPopulateObjectFromSerializedData**

System.Runtime.Serialization.SerializationException : Type 'Octokit.ApiException' in Assembly 'Octokit, Version=0.1.1.0, Culture=neutral, PublicKeyToken=null' is not marked as serializable.

**Octokit.Tests.Http.RateLimitTests+TheConstructor.CanPopulateObjectFromSerializedData**

System.Runtime.Serialization.SerializationException : Type 'Octokit.RateLimit' in Assembly 'Octokit, Version=0.1.1.0, Culture=neutral, PublicKeyToken=null' is not marked as serializable.

**Octokit.Tests.Exceptions.ApiValidationExceptionTests+TheConstructor.CanPopulateObjectFromSerializedData**

System.Runtime.Serialization.SerializationException : Type 'Octokit.ApiValidationException' in Assembly 'Octokit, Version=0.1.1.0, Culture=neutral, PublicKeyToken=null' is not marked as serializable.

**Octokit.Tests.Exceptions.RateLimitExceededExceptionTests+TheConstructor.CanPopulateObjectFromSerializedData**

System.Runtime.Serialization.SerializationException : Type 'Octokit.RateLimitExceededException' in Assembly 'Octokit, Version=0.1.1.0, Culture=neutral, PublicKeyToken=null' is not marked as serializable.

**Octokit.Tests.Reactive.ObservableRepositoriesClientTests+TheGetMethod.IsALukeWarmObservable**

System.ArgumentNullException : Value cannot be null.
Parameter name: uri

Result StackTrace:	
at Octokit.Ensure.ArgumentNotNull(Object value, String name) in c:\Users\brendanforster\Documents\GitHub\octokit.net\Octokit\Helpers\Ensure.cs:line 19
   at Octokit.ApiExtensions.GetAsync[T](IConnection connection, Uri uri) in c:\Users\brendanforster\Documents\GitHub\octokit.net\Octokit\Helpers\ApiExtensions.cs:line 46
   at Octokit.Tests.Reactive.ObservableRepositoriesClientTests.TheGetMethod.<IsALukeWarmObservable>d__4.MoveNext() in c:\Users\brendanforster\Documents\GitHub\octokit.net\Octokit.Tests\Reactive\ObservableRepositoriesClientTests.cs:line 29