title: PowerShell Start-Process not setting $lastexitcode
body: <p>I have a set of test DLL's that I'm running from a powershell script that calls OpenCover.Console.exe via the <code>Start-Process</code> command.</p>
  
  <p>I have the <code>-returntargetcode</code> flag set</p>
  
  <p>After execution I check <code>$lastexitcode</code> and <code>$?</code>. They return 1 and True respectively all the time. Even when tests are failing.</p>
  
  <p>Shouldn't <code>$lastexitcode</code> be 0 when all tests pass and 1 when they fail?</p>