Added support for golang via fatih/vim-go and added necessary Mercurial dependency to install script.
Made tab characters a little more visually pleasing (specifically for Golang) by altering listchars. Also added a convenient shortcut for toggling whether or not listchars are displayed.
Export the necessary environment variables for Golang (particularly $GOROOT which is dynamic and, for some of the tooling and/or documentation to work properly, needs to be set).
A bunch of golang-specific appearance enhancements. Installed the molokai theme that gets used in golang buffers because solarized doesn't look great (IMO). The solarized lightline theme looked goofy with molokai, so I restored that to the default. And a few very specific modifications here and there to prevent artifacting or extra buffers from being spawned.