Fixing a few errors, adding support for attributedPlaceholder

I called it `absoluteFloatLabelOffset`, as the logic inside that method contains the absolute visible/invisible states of the float label. The absolute was put in there to infer the minima and maxima of the float label. I think the word offset is throwing it off.

However, your naming suggestions makes it even more vague. Also, using the prefix `set` without actually having an iVar attached to it is probably taboo :)

In a future version, I'll rename it to `absoluteFloatLabelPosition`. 

Thanks for this suggestion!