If the TITokenFieldView is managing the size of its own contentView, then make sure it adjusts to the TITokenFieldView's scroll inset.

This allows it to be properly positioned in iOS 7 if the nav bar allows views to run underneath it.
Merge pull request #13 from sadlerjw/account-for-scroll-inset

If the TITokenFieldView is managing the size of its own contentView, then make sure it adjusts to the TITokenFieldView's scroll inset.