Removed one more reference to the old compiler

Author: pzgulyas

Source/Orts.Simulation/Orts.Simulation.csproj

@@ -53,9 +53,6 @@
     <Reference Include="MonoGame.Framework">
       <HintPath>$(SolutionDir)\3rdPartyLibs\MonoGame\MonoGame.Framework.dll</HintPath>
     </Reference>
-    <Reference Include="Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=3.6.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL">
-      <HintPath>..\packages\Microsoft.CodeDom.Providers.DotNetCompilerPlatform.3.6.0\lib\net45\Microsoft.CodeDom.Providers.DotNetCompilerPlatform.dll</HintPath>
-    </Reference>
     <Reference Include="Newtonsoft.Json, Version=4.5.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed, processorArchitecture=MSIL">
       <SpecificVersion>False</SpecificVersion>
       <HintPath>..\3rdPartyLibs\Newtonsoft.Json.dll</HintPath>