Make it work with autocomplete

This solves issue #17

Formtastic falls back on to the Formtastic::Inputs module if it didn't find the input class in FormtasticBoostrap::Inputs.

This may not be the best way to solve the autocomplete issue but I need something working quickly. Another way would be to inject the FormtasticBooostrap module into rails3-jquery-autocomplete in place of the vanilla Formtastic module.