Tag v1.4.0

## New Features

- New property `shouldHideAfterDelay` : Tell the MessageBar whether or not it should hide after a delay defined in the `duration` property. If `false`, the MessageBar remain shown
- New property `shouldHideOnTap` : Tell the MessageBar whether or not it should hide or not when the user tap the alert. If `false`, the MessageBar will not hide, but the `onTapped` function is triggered, if defined. In addition, if `false`, the `onHide` function will not be triggered. The property `shouldHideAfterDelay` take precedence over `shouldHideOnTap`. That means if `shouldHideAfterDelay` is `false`, the value of `shouldHideOnTap` is not taken into account, since the MessageBar will not ever be hidden
- New property `titleNumberOfLines` : Number of lines of the title. `0` means unlimited
- New property `messageNumberOfLines` : Number of lines of the message. `0` means unlimited
- New property `titleStyle` : Style of the title
- New property `messageStyle` : Style of the message
- New property `avatarStyle` : Style of the icon/avatar

## Bug Fixes
- When a MessageBar alert is shown it hide the existing one and display a new one, instead of replacing the existing one with its new state (formerly using properties)

## Breaking Changes
- Property `type` renamed to `alertType`