Use Pathogen to make it easy to add Vim bundles
Set Vim theme to Jellybean

I can't get GRB256 to work, so I'll have to settle with this.

This uses Git submodules, so initialize that.  I'll probably add this to
`script/bootstrap` sometime in the future, so I don't need to worry
about this anymore.
Set Vim font to Inconsolata
Show line numbers