Pupeyes

- A better fix for how NA is handled in check_baseline_outliers()
- Added save option for plot_gaze_surface()

- Use strictly True of False for baseline_outlier and trace_ouliter columns in the summary data to avoid pandas ambiguous interpretation of NA in a boolean context.
- Removed some redundant dependencies and relaxed Python version restrictions to hopefully speed up resolving dependencies during install.
- Added plot_gaze_surface() to check gaze position.
- Improved summary stats for filter_position().
- Updated docs to demonstrate plot_gaze_surface()

- First release of `pupeyes`!