Rails extra fix 

RE issue #92 

After some thought, I opted to make `radio_buttons` mimic `collection_radio_buttons` (which themselves might use a few tweaks) though this makes it consistant, at least. 

I also found that `collection_radio_buttons` and `collection_check_boxes` assume that `object` is an object when in certain instances the builder was passed a `Symbol` and `object` is `nil`. And, since the `*_tag` versions were used the symbol is never looked up.  I was able to resolve this for `collection_radio_buttons` by using the builder's `radio_button` method but things are a little tricky with check boxes. Hence the failing tests in Travis.

`ActionView::Helpers::FormHelper.check_box` could be used or one can get the instance var. AFAIK the other helpers have issues in this case.

Oh also, the `collection_*` methods included the Bootstrap options in the `input` element's attributes. This is fixed.