Add styleBase option
Add styleBase option

Provides ability to not use the .btn class on the button. e.g. change
styleBase to 'form-control' and style to 'input-lg'. Close #975. Close
#933.

coopsource/bootstrap-select,performancematters/bootstrap-select,nhahv/bootstrap-select,wearespindle/select3,QthCN/bootstrap-select,iaesaudi/bootstrap-select,silviomoreto/bootstrap-select,bookbrainz/bootstrap-select,bookbrainz/bootstrap-select,TeleginS/bootstrap-select,QthCN/bootstrap-select,tommydevdocs/bootstrap-select,JoachimZ/bootstrap-select,jesenko/bootstrap-select,think2011/bootstrap-select,TeleginS/bootstrap-select,chengky/bootstrap-select,zhaoyan158567/bootstrap-select,think2011/bootstrap-select,chengky/bootstrap-select,anhtranqs3/bootstrap4-select,performancematters/bootstrap-select,tommydevdocs/bootstrap-select,coopsource/bootstrap-select,iaesaudi/bootstrap-select,emilmoe/bootstrap-select,nhahv/bootstrap-select,nayosx/bootstrap-select,Burick/bootstrap-select,wearespindle/select3,silviomoreto/bootstrap-select,anhtranqs3/bootstrap4-select,nayosx/bootstrap-select,JoachimZ/bootstrap-select,emilmoe/bootstrap-select,Burick/bootstrap-select,jesenko/bootstrap-select,zhaoyan158567/bootstrap-select