Add main & dependencies section to bs3 bower.json

Thanks to @xavierdutreilh and @plaflamme for providing PRs
release 1.3.1 for bootstrap3 branch
Remove protocols for jQuery and Select2 sources in gh-pages files –
as kindly suggested by @styfle and @adamjohnson:

 * https://github.com/t0m/select2-bootstrap-css/issues/43
 * https://github.com/fk/select2-bootstrap-css/pull/2
Switch remote example to GitHub Search API.
Snatched from https://github.com/ivaynberg/select2/commit/6661e3d74401d52f4cffffa4f738211a15570279 – thanks to @kevin-brown.
Merge pull request #44 from fk/bootstrap3

Switch gh-pages to protocol-less URLs, remote examples to GitHub Search.
Convert gh-pages CSS to Sass.

 * https://github.com/blog/1867-github-pages-now-runs-jekyll-2-2-0
 * http://jekyllrb.com/docs/assets/
Build select2-bootstrap-css on Twitter Bootstrap v3.2.0.

Update development dependencies:

 * Twitter Bootstrap from v3.0.0 to v3.2.0
 * respond.js from v1.2.0 to v1.4.2
 * jlong/sass-twitter-bootstrap to twbs/bootstrap-sass

Adjust paths in Makefile, fix glitch when copying Bootstrap fonts to _jekyll.
Adjust paths in lib/build.scss, build.less.
Update Less patch.

Update readme - one known issue has been fixed in Bootstrap itself.
Fix Bootstrap version number on docs index page.
Link to select2-bootstrap.css in the bootstrap3 branch, not the one from master.
Replace Makefile tasks with Grunt tasks:

 * replace "make copy_docs_assets" with "grunt copy" (via grunt-contrib-copy)
 * replace "make serve_docs" with "grunt jekyll:build", "make build_docs" with "grunt jekyll:serve" (via grunt-jekyll)
 * replace "make pages" and "make pages_setup" with "grunt gh-pages" (via grunt-gh-pages); note that in contrast to "make pages", "grunt gh-pages" will not (yet) automatically push changes to origin
Add current version number to CSS files, update Bootstrap version.
Update less.patch.
Whitespace in readme.
Alter "grunt gh-pages" to immediately push changes.
Merge pull request #45 from fk/bootstrap3

Build select2-bootstrap-css on Twitter Bootstrap v3.2.0
bootstrap3 release v1.4.0.
Update all docs/gh-pages links to point to the original repository (t0m/select2-bootstrap-css).
Fix indention.
Remove trailing comma.
Fix border-radii for .select2-dropdown-above and select2-dropdown in Bootstrap input groups with addons.

Along the way:

 * add demo pages for Select2 v3.5.1
 * add `grunt watch` for `lib/select2-bootstrap.scss` (with livereload enabled)
 * update readme: add changelog, contributing notes