upgrade to VS2015 and .Net 4.0

shadowsocks-csharp/Properties/Resources.Designer.cs

@@ -1,7 +1,7 @@
 //------------------------------------------------------------------------------
 // <auto-generated>
 //     This code was generated by a tool.
-//     Runtime Version:4.0.30319.34209
+//     Runtime Version:4.0.30319.42000
 //
 //     Changes to this file may cause incorrect behavior and will be lost if
 //     the code is regenerated.

shadowsocks-csharp/shadowsocks-csharp.csproj

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+<Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
@@ -10,7 +10,7 @@
     <AppDesignerFolder>Properties</AppDesignerFolder>
     <RootNamespace>Shadowsocks</RootNamespace>
     <AssemblyName>Shadowsocks</AssemblyName>
-    <TargetFrameworkVersion>v2.0</TargetFrameworkVersion>
+    <TargetFrameworkVersion>v4.0</TargetFrameworkVersion>
     <FileAlignment>512</FileAlignment>
     <StartupObject>
     </StartupObject>
@@ -21,8 +21,7 @@
     <UpgradeBackupLocation>
     </UpgradeBackupLocation>
     <OldToolsVersion>3.5</OldToolsVersion>
-    <TargetFrameworkProfile>
-    </TargetFrameworkProfile>
+    <TargetFrameworkProfile>Client</TargetFrameworkProfile>
     <PublishUrl>publish\</PublishUrl>
     <Install>true</Install>
     <InstallFrom>Disk</InstallFrom>