Fallback through language tags in Localizer

Refactor Localizer loadMessages and add comments
Change locale directory from "locales" to "locale"
Correctly bind localizations for multiple properties on one object
Add better error message for localizations serialization when the key doesn't exist
Make localizer used require packageDescription
Add messagesPromise and timeout to localizer
Make Localizer.localize always return a string even if the message doesn't exist. Friendlier for the user
if downloading the localizations fails
Make Localizer.localizeAsync use the messagesPromise
Add more tests for the localizer
Add script to generate a manifest for the given directories
Add localize function directly on Localizer exports

gh-911
Add delegate to Localizer.defaultLocalizer
Also update JSDoc
gh-903

Seperate out manifest loading in localizer
Add availableLocales property to Localizer
Remove hasMessages from Localizer
Update logger calls in localizer
Add localizer and waitForLocalizerMessages to component

gh-910
Remove incorrect localizer require from component comment

require calls are parsed even if they're in comments.
More informative failure messages in localization spec
Correct rejection to be an error
Update failure handler to match latest Q
Start adding to Message to localizer
Add test for localizer Message object and repetition
Update and refactor MessageLocalizer into Message

and MessageVariables in MessageData
Allow bindable key and default in l10n serialization
Add serializer tests
Change Localizer Message to have key and defaultMessage
Makes Message localize async, and so tests updated
Stop adding dispatchChangeEvent to objects

Unused and polluting objects
Make _bindingDescriptors property non-enumerable
Add serialization support in the localizer