[TIMOB-18954] iOS: Translucent effect of navbar changed with SDK 3.5.0+

Something changed starting with Ti SDK 3.5.0 that affects how the translucent navigation bar is rendered on iOS. With Ti SDK 3.4.1 and below, using the settings on the included sample app.js, the nav bar always rendered dark with light text. The same code on 3.5.0+ always renders the nav bar light, with dark text. One thing I've noticed is that changing the value of statusBarStyle with 3.4.1 (and below) does affect how the nav bar is rendered and toggles it from dark to light depending on the setting. This seems to be the correct behavior, however doing this has no effect with 3.5.0+ and the nav bar *always* renders light. Hopefully there's a quick work around for this. Our app has a dark theme with heavy use of translucency and we cannot upgrade to 3.5.0+ until we get this solved. Setting barColor: '#000000' is not ideal because you loose almost all of the translucency effect, so we keep this property undefined to get the best translucency effect.