Ignore files consistency with common targets file

Also just got rid of .netstandard for now in the main tooling. Keep it simple. Stuff like nunit isn't ready for it and I don't want to fight.

source/Unity.NSubstitute/Unity.NSubstitute.csproj

@@ -1,11 +1,9 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
-  <PropertyGroup>
-    <TargetFramework>netstandard2.0</TargetFramework>
-  </PropertyGroup>
+  <Import Project="../common.targets" />
 
   <PropertyGroup>
-    <DefaultItemExcludes>$(DefaultItemExcludes);**\*.bak</DefaultItemExcludes>
+    <TargetFramework>net461</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>

source/common.targets

@@ -0,0 +1,5 @@
+<Project>
+  <PropertyGroup>
+    <DefaultItemExcludes>$(DefaultItemExcludes);**\*.bak</DefaultItemExcludes>
+  </PropertyGroup>
+</Project>

tests/Support/DependentAssembly/DependentAssembly.csproj

@@ -1,5 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
+  <Import Project="../../../source/common.targets" />
+
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;net35</TargetFrameworks>
   </PropertyGroup>

tests/Support/SystemUnderTest/SystemUnderTest.csproj

@@ -1,5 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
+  <Import Project="../../../source/common.targets" />
+
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;net35</TargetFrameworks>
   </PropertyGroup>

tests/Unity.NSubstitute.Tests/Unity.NSubstitute.Tests.csproj

@@ -1,7 +1,9 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
+  <Import Project="../../source/common.targets" />
+
   <PropertyGroup>
-    <TargetFramework>netstandard2.0</TargetFramework>
+    <TargetFramework>net461</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>