ENYO-3375: fix the non activation of the "Expand All" button as the Palette's filter is used
ENYO-3375: improve code readability
ENYO-3375: fix a wrong icon status
ENYO-3375: fix icon appeareance with css in FF (was always seen as closed)
ENYO-3375: prevent empty categories for tap event
ENYO-3375: improve code by blocking event propagation
ENYO-3375: add Palette's items description as items tooltip
ENYO-3311: resolve jshint errors
ENYO-3375: finally  consider that collapsing or expanding categories has to work on filter results
ENYO-3375: avoid tooltip HTML description coming from API documentation if the component is not handled by a library design file
Merge pull request #711 from enyojs/ENYO-3375-3

ENYO-3375: improve Palette's "Expand/Collapse All" buttons feature