[WIP] Fixes for texlive and doxygen installation

I found some residual bugs in our texlive installation pipeline.  

1.  The download sometimes fails, so it's useful to try the installer twice.  
2.  Don't install texlive from yum
3.  When building doxygen, we have to force ignore dependencies, as texlive is not going to be available as a yum package.  

(2/3) might not be strictly required, but I imagine the cleanest solution is to avoid having two overlapping texlive installs on the same VM, as it could possibly lead to strange PATH / tex include issues in the future.
[EDIT: don't merge just yet, still fixing some silly tex issues]