Enable paragraph styles to use all terminal colors, not just named colors

In variable `StyleParserColorMap` in `style_parser.go`, there is only support for eight colors. I would like the color set to be expanded to all 256 available terminal colors.

The `ParseStyles` function is what is used to apply styles to paragraphs.

Start in style_parser.go by reading the StyleParserColorMap variable and the ParseStyles function that applies styles to paragraphs. Trace how color names become terminal colors, then expand the supported color set to all 256 available terminal colors. Done means paragraph styles can use every terminal color rather than only the current eight.

Written by the indexing model from the issue text.