// Checked on page load:
- add 'checked="checked"' attribute to input

// Disabled on page load:
- add 'disabled="disabled"' attribute to input

// Toggling with radio buttons uses plain old Bootstrap Collapse: 
- See: http://getbootstrap.com/javascript/#collapse
- add `data-toggle="collapse"`
- add `data-target="{{selector}}"`
- optionally consider adding aria attributes `aria-expanded` and `aria-controls`

// Highlighting radio buttons:
- add 'highlight' class to the `.radio` or `.radio-inline` wrapper. This will highlight the radio buttons on check / uncheck.