noneLabels works almost like none but instead of actually adding a row in the list, it will only change the text displayed in the header, when there's no selection.
* renames `select-box-kit` into `select-kit`
* introduces `single-select` and `multi-select` as base components
* introduces {{search-advanced-category-chooser}} as a better component for selecting category in advanced search
* improves events handling in select-kit
* recreates color selection inputs using {{multi-select}} and a custom {{selected-color}} component
* replaces category-selector by a component using select-kit and based on multi-select
* improves positioning of wrapper
* removes the need for offscreen, and instead use `select-kit-header` as a base focus point for all select-kit based components
* introduces a formal plugin api for select-kit based components
* introduces a formal pattern for loading and updating select-kit based components:
```
computeValue()
computeContent()
mutateValue()
```
This commit introduces a mutation on input value given to select-box-kit when value is empty. The refactoring required to avoid this would be too heavy atm, but ultimately we would want to avoid this.
Joffrey JAFFEUX
Robin Ward
Guo Xiang Tan