Fix Travis-CI

[tjvr]

http://shrub.appspot.com/livewires-worksheets/?s=date:d is a dead link

[tjvr]

I'm gonna have the worksheets uploaded straight to the GitHub Releases page. :)

[tjvr]

Having a problem getting the images to build on Travis; I need to find the right package to make EPS support work. Although it looks like Travis' container-based infrastructure doesn't whitelist the relevant package, whatever it is:

Disallowing packages: ps2eps, dvidvi, purifyeps, t1utils, dot2tex, tipa, prosper