herring_mixture_sims: Do the mixture simulations and make some nice ggplots of the...
In eriqande/herring: genetic stock identification of river herring

Quickly threw this together

herring_mixture_sims(baseline_path, lat_long_path, locus_columns, rep_unit_path,
  plot_prefix = "herring", bycatch_N = 1000, random_seed = 50,
  num_rando_mix_props = 50, num_simmed_mixtures = 4, point_size = 1.7,
  point_shape = 1)

`baseline_path`	Path to a baseline file that is in the (csv) format that Dan H uses. See alewife-baseline.csv for an example. Importantly, the file must have a column called Drainage.code that has the drainage codes as in DH's file.
`lat_long_path`	Path to a text file with lats and longs of the pops in the baseline file. See file alewife-lat-long.txt for an example.
`locus_columns`	integer vector with the columns in the original CSV file that have the loci that you want to use. Should be twice as many columns as loci. In alewife-baseline.csv this is
`rep_unit_path`	Path to the reporting unit file
`plot_prefix`	Prefix to put on the plot names
`bycatch_N`	The number of fish in the simulated bycatch samples.
`num_rando_mix_props`	the number of random mixing proportiong to simulate num_simmed_mixtures at.
`num_simmed_mixtures`	the number of mixtures to simulate for each mixing proportion
`point_size`	Size of the points on the plots.