[#1377] Add __init__.py file to example plugin
[#1377] Tidy up first javascript example
[#1377] Add this.options and this.el javascript example
[#1377] Add a snippet API javascript example

This example could be improved by passing only the package id to the
snippet, the snippet can then use h.get_action('package_show')(...) to
get the full package dict.
[#1377] Add docs for snippet API example
[#1377] Add pubsub example and docs
[#1377] Add stubs for remaining sections of js tutorial
[#1377] Fix the case of a title
[#1377] Add best practice about not overusing pubsub
[#1377] Add pubsub working example

This should have been in commit e46df2a6e2cab4326080d50b958b9554284a5bc2
[#1377] Add overview to top of js tutorial
[#1377] Add note about when js modules are initialized
[#1377] Add js error handling example and docs
[#1377] Add stub page for jQuery plugins docs
[#1377] Add jQuery plugin example and docs
[#1377] Use $ and _ param names in JavaScript modules
[#1377] Clarify use of window in JavaScript modules
[#1733] Add 'use strict' to example JavaScript
[#1377] Fix a few little typos etc
[#1377] Use this.$ not this.sandbox.jQuery