Check light curve for nans

[jvines]

Hi,

I recently struggled a while because juliet wasn't running correctly to find out that the light curve file had a single nan point, maybe it could be useful for the code to detect the nan values and either remove them or let the user know this is the case.

Cheers

[nespinoza]

We could, but I really think this is something the user should check. I fear this will always be so far in our priority list that it will never get done, so if anyone feels strongly about this, we are open to Pull Requests :).