Tidy: Sort/remove usings, simplify names

Disco.Services/Extensions/DateTimeExtensions.cs

@@ -1,8 +1,4 @@
 using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 
 namespace Disco
 {

Disco.Services/Extensions/EnumerableExtensions.cs

@@ -1,8 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
+using System.Collections.Generic;
 
 namespace Disco
 {

Disco.Services/Extensions/StringExtensions.cs

@@ -1,8 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 
 namespace Disco
 {

Disco.Services/Extensions/UIHelpers.cs

@@ -2,8 +2,6 @@
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 
 namespace Disco.Services.Extensions
 {