finally gave plot_files the ability to plot full correlators
added an --emass flag to plot_files to compute or plot emasses
much better auto range on plotting
write emass in correlator now uses cosh formula
many improvements to fitter
demoted some warnings to debug
added check symmetric options to correlator
switched to cosh for guessing and allowed amps to be negative
added anti-symmetry option
various improvlemts to plotting and readers