[TIMOB-12451] NavigationBar on iOS has a height of only 43dp

Problem description

The height of the NavigationBar seems to be only 43dp instead of 44dp.

Steps to reproduce

1. Create an Alloy app with the follwing index.xml:

<Alloy>
    <Window class="container">
        <NavigationGroup>
            <Window id="test">
                <Label id="test2">test</Label>
            </Window>
        </NavigationGroup>
    </Window>
</Alloy>

2. Run the code and check the height of the bar (e.g. using a screenshot); it is 43px and not 44 as stated in Apple's docs.

More info

See also http://developer.appcelerator.com/question/147150/alloy---navbar-height-is-wrong When the TabBar is also visible, the NavigationBar has the correct height of 44dp.