RA DEC implementation and temporary fix to issue #1

1. RA and DEC can be passed in to params.py. If nothing is passed to RA and DEC it will work as normal. This is fairly useful if I want to re-download a single target manually rather than re-running the entire period. Also, it does not necessarily require strict dates that I would have to check.

2. NIR images were crashing when closing the fits image. I moved pyfits.flush() to ensure it was always closed before the closing of the image. This should not change the normal functionality (afaics).