Adds support for Floating IP

To @zack-shoylev's comment above that the two `Create` and `Update` classes are a deliberate decision: in that case, at least not name them `...Options`? Classes like that in jclouds are widely used to specify additional query attributes, **not** the domain object itself. If they're really needed, how about `CreateFloatingIP` and `UpdateFloatingIP` or `FloatingIPToCreate` and `FloatingIPToUpdate` or so?