Changed from C# 5 to 6

src/Numerics/Numerics.csproj

@@ -44,7 +44,7 @@
     <WarningLevel>4</WarningLevel>
     <CodeAnalysisRuleSet>AllRules.ruleset</CodeAnalysisRuleSet>
     <NoWarn>1591</NoWarn>
-    <LangVersion>5</LangVersion>
+    <LangVersion>6</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
     <OutputPath>..\..\out\lib-debug\Net40\</OutputPath>
@@ -75,7 +75,7 @@
     <WarningLevel>4</WarningLevel>
     <CodeAnalysisRuleSet>AllRules.ruleset</CodeAnalysisRuleSet>
     <NoWarn>1591</NoWarn>
-    <LangVersion>5</LangVersion>
+    <LangVersion>6</LangVersion>
   </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />