- Fixed how r_min is calculated.

- Changed how the lightcurve sample rate is calculated, it is now derived directly from the lightcurve instead of from a hard-coded value.  This allows us to run arbitrarily-sampled lightcurves through bls_pulse without extra logic and keywords, as long as those lightcurves have enough data points so that the median of the time differences between each point is a good estimate of the actual lightcurve sampling rate.  This should be true even for a single Kepler Quarter, and certainly true for simulated data if the simulated data is using a constant sampling and doesn't have (many) gaps.