Remove stupid _site directory.
Update .gitignore to ignore the _site directory.
Change config to use baseurl instead of url so that running Jekyll
locally works.
Added a Gemfile to aid with above local Jekyll installation.
Replaced images of equations with LaTeX, which is much prettier.
Merge branch 'gh-pages' of https://github.com/Electrostatics/apbs-pdb2pqr into gh-pages