assets: upgrade bootstrap to 2.3.0

Signed-off-by: Pierre-Alexandre Meyer <pierre@ning.com>
Docs updates

Signed-off-by: Pierre-Alexandre Meyer <pierre@ning.com>
Merge branch 'gh-pages' of github.com:killbill/killbill into gh-pages

Signed-off-by: Pierre-Alexandre Meyer <pierre@ning.com>

Conflicts:
	start.html