The supplied Timeline object as defined in 'timeline.js' can be further modified by direct editing of the code. Such work requires a reasonable degree of JavaScript expertise and familiarity of object-oriented use of JS.
Note the header comments in the library. If in doubt about the legality of any edits do drop a line to Eastgate. For instance, deliberately removing the 'made with Tinderbox' label would require express permission of Eastgate.