Add ISftpClient interface to SftpClient (#197)

Add ISftpClient interface to **SftpClient for mocking and testing purposes.
Fixes #193.

Author: ericbrumfield

src/Renci.SshNet.Silverlight/Renci.SshNet.Silverlight.csproj

@@ -1183,6 +1183,9 @@
     </Compile>
     <Compile Include="..\Renci.SshNet\SftpClient.cs">
       <Link>SftpClient.cs</Link>
+    </Compile>
+	<Compile Include="..\Renci.SshNet\ISftpClient.cs">
+      <Link>ISftpClient.cs</Link>
     </Compile>
     <Compile Include="..\Renci.SshNet\Sftp\Flags.cs">
       <Link>Sftp\Flags.cs</Link>

src/Renci.SshNet.Silverlight5/Renci.SshNet.Silverlight5.csproj

@@ -1189,6 +1189,9 @@
     </Compile>
     <Compile Include="..\Renci.SshNet\SftpClient.cs">
       <Link>SftpClient.cs</Link>
+    </Compile>
+	<Compile Include="..\Renci.SshNet\ISftpClient.cs">
+      <Link>ISftpClient.cs</Link>
     </Compile>
     <Compile Include="..\Renci.SshNet\Sftp\Flags.cs">
       <Link>Sftp\Flags.cs</Link>

src/Renci.SshNet.UAP10/Renci.SshNet.UAP10.csproj

@@ -381,6 +381,9 @@
     <Compile Include="..\Renci.SshNet\ISession.cs">
       <Link>ISession.cs</Link>
     </Compile>
+    <Compile Include="..\Renci.SshNet\ISftpClient.cs">
+      <Link>ISftpClient.cs</Link>
+    </Compile>
     <Compile Include="..\Renci.SshNet\ISubsystemSession.cs">
       <Link>ISubsystemSession.cs</Link>
     </Compile>

src/Renci.SshNet.WindowsPhone/Renci.SshNet.WindowsPhone.csproj

@@ -1168,6 +1168,9 @@
     </Compile>
     <Compile Include="..\Renci.SshNet\SftpClient.cs">
       <Link>SftpClient.cs</Link>
+    </Compile>
+	<Compile Include="..\Renci.SshNet\ISftpClient.cs">
+      <Link>ISftpClient.cs</Link>
     </Compile>
     <Compile Include="..\Renci.SshNet\Sftp\Flags.cs">
       <Link>Sftp\Flags.cs</Link>

src/Renci.SshNet.WindowsPhone8/Renci.SshNet.WindowsPhone8.csproj

@@ -358,6 +358,9 @@
     <Compile Include="..\Renci.SshNet\ISession.cs">
       <Link>ISession.cs</Link>
     </Compile>
+    <Compile Include="..\Renci.SshNet\ISftpClient.cs">
+      <Link>ISftpClient.cs</Link>
+    </Compile>
     <Compile Include="..\Renci.SshNet\ISubsystemSession.cs">
       <Link>ISubsystemSession.cs</Link>
     </Compile>
@@ -1441,7 +1444,7 @@
   <Import Project="$(MSBuildExtensionsPath)\Microsoft\$(TargetFrameworkIdentifier)\$(TargetFrameworkVersion)\Microsoft.$(TargetFrameworkIdentifier).CSharp.targets" />
   <ProjectExtensions>
     <VisualStudio>
-      <UserProperties ProjectLinkerExcludeFilter="\\?desktop(\\.*)?$;\\?silverlight(\\.*)?$;\.desktop;\.silverlight;\.xaml;^service references(\\.*)?$;\.clientconfig;^web references(\\.*)?$" ProjectLinkReference="2f5f8c90-0bd1-424f-997c-7bc6280919d1" />
+      <UserProperties ProjectLinkReference="2f5f8c90-0bd1-424f-997c-7bc6280919d1" ProjectLinkerExcludeFilter="\\?desktop(\\.*)?$;\\?silverlight(\\.*)?$;\.desktop;\.silverlight;\.xaml;^service references(\\.*)?$;\.clientconfig;^web references(\\.*)?$" />
     </VisualStudio>
   </ProjectExtensions>
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 

src/Renci.SshNet/ISftpClient.cs

@@ -16,7 +16,7 @@ namespace Renci.SshNet
     /// <summary>
     /// Implementation of the SSH File Transfer Protocol (SFTP) over SSH.
     /// </summary>
-    public class SftpClient : BaseClient
+    public class SftpClient : BaseClient, ISftpClient
     {
         private static readonly Encoding Utf8NoBOM = new UTF8Encoding(false, true);