Remove custom BaseIntermediateOutputPath

Now that the signed projects have unique assembly names, we can have the same "obj" folder again.
This removes a custom setup that is not necessary and caused problems with .NET Core SDK 2.x.

Author: angularsen

UnitsNet.Serialization.JsonNet/UnitsNet.Serialization.JsonNet.Common.props

@@ -23,7 +23,6 @@
     <RootNamespace>UnitsNet.Serialization.JsonNet</RootNamespace>
     <!-- Workaround for building with dotnet CLI and targeting .NET 3.5: https://github.com/Microsoft/msbuild/issues/1333#issuecomment-296346352 -->
     <FrameworkPathOverride Condition="'$(TargetFramework)' == 'net35'">C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v3.5\Profile\Client</FrameworkPathOverride>
-    <BaseIntermediateOutputPath>obj\$(MSBuildProjectName)</BaseIntermediateOutputPath>
     <OutputPath>..\Artifacts\$(MSBuildProjectName)</OutputPath>
     <NoWarn>CS0618</NoWarn>
   </PropertyGroup>

UnitsNet/UnitsNet.Common.props

@@ -15,7 +15,6 @@
     <PackageLicenseUrl>https://github.com/angularsen/UnitsNet/blob/master/LICENSE</PackageLicenseUrl>
     <PackageRequireLicenseAcceptance>false</PackageRequireLicenseAcceptance>
     <PackageTags>unit units quantity quantities measurement si metric imperial abbreviation abbreviations convert conversion parse immutable</PackageTags>
-    <BaseIntermediateOutputPath>obj\$(MSBuildProjectName)</BaseIntermediateOutputPath>
     <OutputPath>..\Artifacts\$(MSBuildProjectName)</OutputPath>
   </PropertyGroup>