Fix tests that don't work on the build server (apparently .pdf and .docx file extentions are not recognised by Windows out of the box)
Fix tests that don't work on the build server (apparently .pdf and .docx file extentions are not recognised by Windows out of the box)

TDaphneB/XeroAPI.Net,XeroAPI/XeroAPI.Net,jcvandan/XeroAPI.Net,MatthewSteeples/XeroAPI.Net