sublime text: enable spellcheck
sublime text: :lipstick: auto-resort preferences key/value pairs.
sublime text: improve utility packages.

Add HTML-CSS-JS Prettify and Keymaps packages.
sublime text: add SublimeLinter-csslint package.
sublime text: improve JS completions.

Add JavaScript Snippets and Node Completions packages.
nvm: bump to v0.20.0.
rbenv-plugins: bump ruby-build to v20141128.