Merge pull request #141 from DataObjects-NET/6.0-vs-compatibility-fix

Design-time build runs through very limited targets and does not provide
any libraries so we can skip weaving. VS runs normal build at some point
anyway so it should not hurt anybody but improve VS responsiveness
and user experience.

Author: alex-kulakov

MSBuild/DataObjects.Net.targets

@@ -21,7 +21,7 @@
         Inputs="@(IntermediateAssembly -> '%(FullPath)')"
         Outputs="@(IntermediateAssembly -> '%(FullPath).weaver-stamp')"
         DependsOnTargets="ResolveAssemblyReferences;_CopyFilesMarkedCopyLocal;$(XtensiveOrmBuildDependsOn)"
-        Condition="'$(XtensiveOrmSkipProcessing)'!='true'">
+        Condition="'$(XtensiveOrmSkipProcessing)'!='true' AND '$(DesignTimeBuild)' != 'true'">
   <Error Condition="!Exists('$(XtensiveOrmWeaver)')"
          Text="Weaver is not found at '$(XtensiveOrmWeaver)'" />
   <Message Importance="low" Text="Using weaver at '$(XtensiveOrmWeaver)'" />