add custom selectbox components
add keyboard control and some styles
- rename selectbox into listbox (from the aria role attribute)
- code cleaning & refactoring
- add accessibility behaviour & control
- style elements using aria attributes instead of classes (removed classes)
- expand keyboard control
update README
move private function to public method (to avoid jshint error from binding 'this' context)
remove stuff from the markup + trying to upgrade icon font css
Merge branch 'icon' into tooltip
start using CSS attribute selector + rework the tooltip living with icon font
Merge branch 'listbox'

Conflicts:
	js/placeholderLabel.js
	scss/_icons.scss