Merge pull request #18 from luiz/master

Adding portuguese localization
update to better-dom 2, use boilerplate
fix tests, use more ES6 stuff
update readme, remove .jshintrc
minor fixes and cleanup
use css variables
extract some VK constants
intial support for animatable datepicker
improve text css
fix calendar days animation
improve calendar styles
improve date picker markup
improve calendar css
initial implementation of doFormatValue
don't need to update days of week everytime
simplify code, improve calendar styles
initial support for min/max attributes
fix specs
improve css, update demo
minor refactoring