bootstrap3 v3.4.2

 * Removed box-shadow for `.select2-container.form-control` (inherited from Bootstrap's `.form-control`).
 * Fixed [#35](https://github.com/t0m/select2-bootstrap-css/issues/35).
 * Removed border-left for `.select2-arrow` ([#36](https://github.com/t0m/select2-bootstrap-css/issues/36))
 * Built on Bootstrap 3 v3.3.1 and corresponding bootstrap-sass.
 * Bower components now live in the default "bower_components" folder; ditched grunt-jekyll in favor of grunt-shell.
 * Updated grunt plugins.