Attempt to build the document using github actions. (#657)

* Attempt to build the document using github actions.

Travis stopped working, and it's always been a bit voodoo to me.

* Install sympy

* Install pdflatex.

* Install pdftexcmds.sty

* Mess with newlines.

* Install letltxmacro.sty

* Install bbding.sty

* Install algorithmicx.sty

* Also `make chisel`

* Remove travis check.