Summary:
Hi,
I've updated the NavigatorIOS component to allow setting the translucent property.
usage is:
```
<NavigatorIOS
translucent={false}
/>
```
This is my first contrib to react-native, so apologies if I've missed something.
Cheers,
Owen
Closes https://github.com/facebook/react-native/pull/1273
Github Author: Owen Kelly <owen@novede.com>
Test Plan: Imported from GitHub, without a `Test Plan:` line.
1cca4fb769