Inline calls to the deprecated StringHelper.compare

In an attempt to limit the number of warnings during compilation I though it'd be nice to clean up our own stuff. This is a start: StringHelper.compare is used throughout the code and is delegated to FutureArrays (where it belongs, as the arguments are byte[], not Strings).

This can cause other patches to not apply anymore... so we could apply this to master only. If anybody has a strong feeling about it, please voice it. The patch is trivial.