Update SpecFlowHelper to search for tools folder

Changed default SpecFlowHelper ToolPath to search sub folders for the correct tools directory so you don't have to change this for each new version of SpecFlow.  Works same as NUnit.
Update SpecFlowHelper to search for tools folder

Fixed initial change to include toolname variable.
Merge pull request #496 from ssteward54/patch-2

Update SpecFlowHelper to search for tools folder