The bottomTab settings were not being properly applied if a SplitView
controller was nested. Part of this seems to be that the 'options' for
SplitView were in their V1 form, i.e. they did not have access to the
full topBar/bottomTab/etc.

I refactored the options to be in their own subsettings. NOTE: the
settings for splitView are not being applied currently -- they weren't
before and they still are not now.

With access to the full options now, I was able to change
RNNSplitViewController to properly override
willMoveToParentViewController to get the bottomTab icon to properly
show up.