Merge pull request #220 from llwt/develop

add option to configure icon prefix
Right counting <li> in nested collections

Although this does not affect the functionality of the bundle, it really makes html look prettier.
Update bc-bootstrap-collection.js
Merge pull request #224 from sandello-alkr/patch-4

Right counting <li> in nested collections
Add optional parameter to iconFunction of twig extension to override default icon prefix