Moved IThumbnailProvider interface to root of Umbraco.Core assembly

src/Umbraco.Core/IThumbnailProvider.cs

@@ -3,7 +3,7 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 
-namespace Umbraco.Core.Interfaces
+namespace Umbraco.Core
 {
     public interface IThumbnailProvider
     {

src/Umbraco.Core/Umbraco.Core.csproj

@@ -47,7 +47,7 @@
     <Compile Include="DelegateEqualityComparer.cs" />
     <Compile Include="EnumerableExtensions.cs" />
     <Compile Include="IfExtensions.cs" />
-    <Compile Include="Interfaces\IThumbnailProvider.cs" />
+    <Compile Include="IThumbnailProvider.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="StringAliasCaseType.cs" />
     <Compile Include="StringExtensions.cs" />