move ioutils.py, logs.py into analyses/
new analyses/__init__.py
update imports
move functions from fit_von_mises.py into new files in analyses/
new .gitignore
move fit() into analyses/fit_mixture.py, update fit_von_mises.py

- new get_options_parser(), get_start_params(), split_dir_base()
fix trailing LFs (closes #9)
new VonMisesMixture.fit() - normalize parameters
new DataSource, use it in fit_von_mises.py()

new Struct.__init__()
move plotting from fit_von_mises.py to analyses/plots.py

new plot_raw_data(), plot_estimated_dist(), plot_histogram_comparison()
remove negative kappa flag (useless when using parameter normalization)

- update CSVLog
move logging from fit_von_mises.py into new log_results()