Use iter_bursts_start_stop() in Data.iter_bursts_ph()
Update and fix calc_mean_lifetime()
HDF5: Remove nanotimes_unit from store and loader
HDF5: Do not overwrite an HDF5 file that is being re-saved.
HDF5: handle both ALEX and non-ALEX 1-spot data
HDF5: rename nanotime -> nanotimes
Address deprecation warning of '-' operator on bool arrays in numpy 1.9