Update ion-md-input.js
Update ion-md-input.js

Use 'add' instead of 'toggle' to stop the lable droping into input box when it does have a value.
Calling add from classList will not add extra class if it alreay exists.
denzelwamburu/ion-md-input,denzelwamburu/ion-md-input,mhartington/ion-md-input,mhartington/ion-md-input