FEATURE: Native theme support

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

app/assets/javascripts/admin/components/inline-edit-checkbox.js.es6

@@ -0,0 +1,36 @@
+import {default as computed, observes} from "ember-addons/ember-computed-decorators";
+
+export default Ember.Component.extend({
+  init(){
+    this._super();
+    this.set("checkedInternal", this.get("checked"));
+  },
+
+  classNames: ['inline-edit'],
+
+  @observes("checked")
+  checkedChanged() {
+    this.set("checkedInternal", this.get("checked"));
+  },
+
+  @computed("labelKey")
+  label(key) {
+    return I18n.t(key);
+  },
+
+  @computed("checked", "checkedInternal")
+  changed(checked, checkedInternal) {
+    return (!!checked) !== (!!checkedInternal);
+  },
+
+  actions: {
+    cancelled(){
+      this.set("checkedInternal", this.get("checked"));
+    },
+
+    finished(){
+      this.set("checked", this.get("checkedInternal"));
+      this.sendAction();
+    }
+  }
+});