Prevent call to $setViewValue if value not changed
Prevent call to $setViewValue if value not changed

In IE11, even with newer versions of angular, placeholder can still cause an input event to be raised in some scenarios, which gets registered as an attempt to delete when no value has been entered yet, causing the form to be dirty immediately.
RafaelTaranto/ui-mask,lukepfeiffer10/ui-mask,angular-ui/ui-mask,isaacplmann/ui-mask,isaacplmann/ui-mask,lukepfeiffer10/ui-mask,RafaelTaranto/ui-mask