* 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 way they can be replaced by plugins without conflicting with other
icons. For example `circle` is used in some places that doesn't
represent `tracking`.
This feature introduces the concept of themes. Themes are an evolution
of site customizations.
Themes introduce two very big conceptual changes:
- A theme may include other "child themes", children can include grand
children and so on.
- A theme may specify a color scheme
The change does away with the idea of "enabled" color schemes.
It also adds a bunch of big niceties like
- You can source a theme from a git repo
- History for themes is much improved
- You can only have a single enabled theme. Themes can be selected by
users, if you opt for it.
On a technical level this change comes with a whole bunch of goodies
- All CSS is now compiled using a custom pipeline that uses libsass
see /lib/stylesheet
- There is a single pipeline for css compilation (in the past we used
one for customizations and another one for the rest of the app
- The stylesheet pipeline is now divorced of sprockets, there is no
reliance on sprockets for CSS bundling
- CSS is generated with source maps everywhere (including themes) this
makes debugging much easier
- Our "live reloader" is smarter and avoid a flash of unstyled content
we run a file watcher in "puma" in dev so you no longer need to run
rake autospec to watch for CSS changes
