Graphics improvements

Defaults to show minor grid and fixed bug where minor grid preference
was stripped out of template.

Styles.json can now contain not just color preference but also line type
or any other "glyph" parameter.  A list can be provided which is taken
in order given to delineate multiple curves.  These changes improve
support for multiple curves from the same alternative on one plot and
plotting in monochrome.
updated changelog
PDF output for plots using Adobe Distiller