error when param 29 is empty or is 0,0 in pairddrad

[charmichaeld]

Found issue in PyRAD 3.0.66 with the dataset: http://www.dereneaton.com/downloads/simpairddrads.zip
Step 6 fails in pairddrad mode if ## 29.opt has an empty value or if the value is 0,0
I had to set the value to 1,1 for pyRAD to complete successfully
pyRAD.py -p params.txt -s 1234567
I used single end data and PyRAD worked as expected when using rad mode with the value of ## 29.opt set to 0,0