listen to programmatic value changes on input element
Merge branch 'listen-to-programmatic-changes' of https://github.com/tomru/rangeslider.js into tomru-listen-to-programmatic-changes

* 'listen-to-programmatic-changes' of https://github.com/tomru/rangeslider.js:
  listen to programmatic value changes on input element
Merged develop into tomru-listen-to-programmatic-changes
Listen to programmatic value changes
Merge pull request #25 from andreruffert/tomru-listen-to-programmatic-changes

Listen to programmatic value changes on input element