Switched from jslint to jshint.

Jesse Hallett's jslint.vim is no longer under active development. There
is an actively developed fork of jslint.vim, which is called jshint.vim.
As the name implies, it is based on jshint rather than jslint.
  https://github.com/hallettj/jslint.vim
  https://github.com/wookiehangover/jshint.vim

jshint allows you to define your settings in a .jshintrc file. It looks
first for .jshintrc, then ../.jshintrc, then ../../.jshintrc, etc.  This
is nice, since it you no longer need ugly 'directive' comments in the
*.js files. Plus, it allows you to centralize your standard settings.

Setting up Vim to use jshint is done by executing these commands:
  mkdir -p ~/.vim/bundle/vim-pathogen/autoload
  curl -Sso ~/.vim/bundle/vim-pathogen/autoload/pathogen.vim \
       https://raw.github.com/tpope/vim-pathogen/master/autoload/pathogen.vim
  cd ~/.vim/bundle
  git clone https://github.com/wookiehangover/jshint.vim.git
and then prepending these lines to your .vimrc:
  runtime bundle/vim-pathogen/autoload/pathogen.vim
  execute pathogen#infect()
Also, add these lines to your .vimrc if they're not there already:
  syntax on
  filetype plugin indent on
Tweaked jshint options to suit my preferences
Removed spurious line used for testing jshint settings
Merge branch 'jshint-conversion' (replacing jslint with jshint).