Fossil SCM

Changed the timeline highlight colors so that the secondary value (used in e.g. /vdiff&to) is a lighter and more saturated version of the primary accent color, being the header font color, and the secondary is a one-eighty hue shift on this. This results in a small color difference for the former, more complementary to the overall skin colors but still a light blue. The primary color — used in /info timelines and for the /vdiff&from cell — is more significantly shifted, a pale orange now rather than a bright yellow. This results from basic color theory; to maintain a yellow under this one-eighty hue rule, we'd have to make the secondary color purple, not blue. Inskinerator Modern uses that rule to shift all the ancillary colors when you shift one of the primaries, saving the user from having to specify each derived color name manually. Fossil's hard-coded skins don't have that same motivation, and as hard-coded defaults, the old "office highlighter" colors were fine, but once you get down to specific instances, we don't want to use arbitrary color, we want them to be analogous or complementary to the main accent color.