Emote Menu? Emote Menu.

* Add the emote menu.
* Add an option to replace the emote menu icon with the FFZ icon.
* Add icons to the icon font.
* Add a basic human duration formatting method to i18n.
* Add methods to the emotes module to get sets including the providers.
* Add a method to the emotes module to load an arbitrary set.
* Add a map to the emotes module for identifying providers.
* Add new events for when emote sets change.
* Add support for loading featured channel emotes.
* Add an option to suppress source sets in emote tooltips.
* Add an option to display a sellout line in emote tooltips.
* Remove emote menu from the WIP section of the home page of the menu.
* Fix a typo in rich content.
* Remove a bit of logging from fine.
* Add helper methods for set comparison and basic debouncing to utilities/object.
* Add constants for the emote menu.
* Add methods to show/hide a tooltip to the tooltip data object.

src/utilities/object.js

@@ -39,6 +39,39 @@ export function timeout(promise, delay) {
 }
 
 
+/**
+ * Make sure that a given asynchronous function is only called once
+ * at a time.
+ */
+
+export function once(fn) {
+	let waiters;
+
+	return function(...args) {
+		return new Promise(async (s,f) => {
+			if ( waiters )
+				return waiters.push([s,f]);
+
+			waiters = [[s,f]];
+			let result;
+			try {
+				result = await fn.call(this, ...args); // eslint-disable-line no-invalid-this
+			} catch(err) {
+				for(const w of waiters)
+					w[1](err);
+				waiters = null;
+				return;
+			}
+
+			for(const w of waiters)
+				w[0](result);
+
+			waiters = null;
+		})
+	}
+}
+
+
 /**
  * Check that two arrays are the same length and that each array has the same
  * items in the same indices.
@@ -59,6 +92,18 @@ export function array_equals(a, b) {
 }
 
 
+export function set_equals(a,b) {
+	if ( !(a instanceof Set) || !(b instanceof Set) || a.size !== b.size )
+		return false;
+
+	for(const v of a)
+		if ( ! b.has(v) )
+			return false;
+
+	return true;
+}
+
+
 /**
  * Special logic to ensure that a target object is matched by a filter.
  * @param {object} filter The filter object