Fix wrapper options
Fix wrapper options

The wrapper options must be retrieved from css_options to work for every control and it must be merged (instead of reverse_merged) because empty form_group_options values prevent a reverse_merge to work (and if we specify things in wrapper, they should always be considered as more important than default options).

Fix #153
ccasabona/rails-bootstrap-forms,desheikh/rails-bootstrap-forms,vincedevendra/rails-bootstrap-forms,Stellenticket/rails-bootstrap-forms,jdugarte/rails-bootstrap-forms,joostliketoast/rails-bootstrap-forms,Axxiss/rails-bootstrap-forms,vincedevendra/rails-bootstrap-forms,bootstrap-ruby/rails-bootstrap-forms,claimsmall/rails-bootstrap-forms,Stellenticket/rails-bootstrap-forms,orenmazor/rails-bootstrap-forms,ccasabona/rails-bootstrap-forms,claimsmall/rails-bootstrap-forms,orenmazor/rails-bootstrap-forms,crslade/rails-bootstrap-forms,Axxiss/rails-bootstrap-forms,Axxiss/rails-bootstrap-forms,joostliketoast/rails-bootstrap-forms,donv/rails-bootstrap-forms,pinoss/rails-bootstrap-forms,pinoss/rails-bootstrap-forms,pinoss/rails-bootstrap-forms,jdugarte/rails-bootstrap-forms,jdugarte/rails-bootstrap-forms,ccasabona/rails-bootstrap-forms,desheikh/rails-bootstrap-forms,crslade/rails-bootstrap-forms,orenmazor/rails-bootstrap-forms,PsiRadish/rails-bootstrap-forms,zBMNForks/rails-bootstrap-forms,desheikh/rails-bootstrap-forms,PsiRadish/rails-bootstrap-forms,Stellenticket/rails-bootstrap-forms,crslade/rails-bootstrap-forms,zBMNForks/rails-bootstrap-forms,zBMNForks/rails-bootstrap-forms,vincedevendra/rails-bootstrap-forms,joostliketoast/rails-bootstrap-forms,PsiRadish/rails-bootstrap-forms,claimsmall/rails-bootstrap-forms