added Bootstrap 3 support and some options
added Bootstrap 3 support and some options

Now it can add the button before the input, create button and input container when class are set, and can create Bootstrap input group.
r11runner/bootstrap-filestyle,thiagocarlossilverio/bootstrap-filestyle,gnachao/bootstrap-filestyle,JoseVte/bootstrap-filestyle,r11runner/bootstrap-filestyle,acemaster/bootstrap-filestyle,gnachao/bootstrap-filestyle,markusslima/bootstrap-filestyle,ar-icom/bootstrap-filestyle,markusslima/bootstrap-filestyle,thiagocarlossilverio/bootstrap-filestyle,ar-icom/bootstrap-filestyle,acemaster/bootstrap-filestyle,becompany/bootstrap-filestyle,becompany/bootstrap-filestyle,JoseVte/bootstrap-filestyle