Datepicker doesn't update value on clear.

[clov3r]

Given this

    {{md-input-date label='Start Date' value=startDate}}

I click the input and select October 5th, 2015, startDate is set to the chosen date.

Click the input again, and click "Clear", the input field appears empty, but startDate is still October 5th, 2015.

[clov3r]

Sorry, pressed tab, then space, and submitted the issue before I was finished typing. Edited the above to make sense.

Using ember-cli-materialize v0.18.6, ember v 1.13.10, ember-cli v 1.13.8.