add code sample in current components.html

Navs, Navbar, Breadcrumb, Pagination
update Gruntfile

- add new task "multi-select" to copy files of "Bootstrap Multiselect" plugin
 - http://davidstutz.github.io/bootstrap-multiselect/
[#73183568add]update dropdowns

- add code sample for each patterns
- add new dropdown pattern which is combined with input elements
  - for this pattern, uses plugins
    - Bootstrap Multiselect  http://davidstutz.github.io/bootstrap-multiselect/