add touch-up paint code table from parts page

Keep all the paint code data on one page.
improve paint code table formatting - use thead and caption elements
add parts page

This page is currently hard to reach since there's no path to it from
the top level.  You can get to it from a link on the horn history
page, though.  We need to decide whether to split the "Parts/Service"
tab into two tabs now that we've got the nice dynamic service locator.
Merge branch 'master' of github.com:erimille/5united