utils: HTML ID washer

* Add utility for cleaning strings such that they can be used as HTML IDs,
without generating, for example, jQuery issues. Such strings must start with
a lowercase letter and use only alpha-numeric characters. Unit tests included.

Signed-off-by: Adrian-Tudor Panescu <adrian.tudor.panescu@cern.ch>
static: bindModals focus element specification

* Allow specifying on what element to focus when opening a modal. Useful for
forms.

Signed-off-by: Adrian-Tudor Panescu <adrian.tudor.panescu@cern.ch>
comments: tests import fix

Signed-off-by: Adrian-Tudor Panescu <adrian.tudor.panescu@cern.ch>
comments: collapse.js refactoring

* Export collpase toggle functions as module.

Signed-off-by: Adrian-Tudor Panescu <adrian.tudor.panescu@cern.ch>
Merge pull request #62 from adrianp/pu-fixes

Minor fixes and additions