Some clean-up of Ix.

Ix.NET/Source/System.Interactive/Buffer.cs

@@ -2,10 +2,7 @@
 // The .NET Foundation licenses this file to you under the Apache 2.0 License.
 // See the LICENSE file in the project root for more information. 
 
-using System;
 using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 
 namespace System.Linq
 {
@@ -80,4 +77,4 @@ namespace System.Linq
     public interface IBuffer<out T> : IEnumerable<T>, IDisposable
     {
     }
-}
+}

Ix.NET/Source/System.Interactive/Case.cs

@@ -59,4 +59,4 @@ namespace System.Linq
                          });
         }
     }
-}
+}

Ix.NET/Source/System.Interactive/Catch.cs

@@ -2,10 +2,7 @@
 // The .NET Foundation licenses this file to you under the Apache 2.0 License.
 // See the LICENSE file in the project root for more information. 
 
-using System;
 using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 
 namespace System.Linq
 {
@@ -150,4 +147,4 @@ namespace System.Linq
                 throw error;
         }
     }
-}
+}

Ix.NET/Source/System.Interactive/Concatenate.cs

@@ -2,10 +2,7 @@
 // The .NET Foundation licenses this file to you under the Apache 2.0 License.
 // See the LICENSE file in the project root for more information. 
 
-using System;
 using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 
 namespace System.Linq
 {
@@ -46,4 +43,4 @@ namespace System.Linq
                     yield return item;
         }
     }
-}
+}

Ix.NET/Source/System.Interactive/Create.cs

@@ -2,11 +2,8 @@
 // The .NET Foundation licenses this file to you under the Apache 2.0 License.
 // See the LICENSE file in the project root for more information. 
 
-using System;
 using System.Collections;
 using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 
 namespace System.Linq
 {
@@ -64,4 +61,4 @@ namespace System.Linq
             }
         }
     }
-}
+}

Ix.NET/Source/System.Interactive/Defer.cs

@@ -2,10 +2,7 @@
 // The .NET Foundation licenses this file to you under the Apache 2.0 License.
 // See the LICENSE file in the project root for more information. 
 
-using System;
 using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 
 namespace System.Linq
 {
@@ -31,4 +28,4 @@ namespace System.Linq
                 yield return item;
         }
     }
-}
+}