Fix Ntupler so that it compiles and runs

Hi Brian,

I was testing out your code to see if there was something weird going on with the dataset, and it seemed like your github wasn't up to date on the fixes we implemented before.  I fixed them just now (don't worry, it was quick :)).  If you want to merge them, feel free to do so.  If not, I'd recommend fixing it on your own and then pushing the fix commit(s) to your repository so that you have a working version :).

-SK