title: MSBuild Artifactory Plugin build error
body: <p>I'm trying to work with MSBuild Artifactory Plugin. I followed the steps from this video: <a href="https://www.youtube.com/watch?v=qV0VqsAOcoU" rel="nofollow">https://www.youtube.com/watch?v=qV0VqsAOcoU</a>.  I tried building the solution using VS 2015 and TFS, but the build is giving me the following error:-</p>
  
  <p>.artifactory\Deploy.targets(26,5): Error : [Artifactory] Exception from Artifactory Task: Could not extract targetBuilderCallback from Microsoft.Build.BackEnd.TaskHost
  C:\TfsBuildAgents\Agent-test-TEST_work\4\s.artifactory\Deploy.targets(26,5): error : [Artifactory] Exception from Artifactory Task: Could not extract targetBuilderCallback from Microsoft.Build.BackEnd.TaskHost [C:\TfsBuildAgents\Agent-test-TEST_work\4\s\Artifactory1\Artifactory1.csproj]
  .artifactory\Deploy.targets(26,5): Error : Could not extract targetBuilderCallback from Microsoft.Build.BackEnd.TaskHost
  at JFrog.Artifactory.BuildEngineExtensions.GetProjectInstance(IBuildEngine buildEngine)
  at JFrog.Artifactory.BuildEngineExtensions.GetEnvironmentVariable(IBuildEngine buildEngine, String key, Boolean throwIfNotFound)
  at JFrog.Artifactory.Utils.SolutionHandler.MsbuildInterpreter(FileInfo artifactoryConfigurationFile, ArtifactoryBuild task)
  at JFrog.Artifactory.Utils.SolutionHandler.GetMainConfiguration()
  at JFrog.Artifactory.Utils.SolutionHandler..ctor(ArtifactoryBuild task, BuildInfoLog log)
  at JFrog.Artifactory.ArtifactoryBuild.Execute()</p>
  
  <p>What am I missing?</p>