Put temporary file in %TEMP% on Windows

May potentially fix issue 76, as the filenames returned by os.tmpname()
were going into my C drive root directory due to the \ in the front.
I suspect that some people may not have user permissions to read/write
to the root of their C drive. I don't know why os.tmpname() does not
give a file in %TEMP% on Windows like it does on Linux. Maybe it's a
bug.