Add demo site

[patrickberkeley]

Create a demo site:

Features

Explore key names

• ability to expose event.key name when a key is triggered

Try out macros

• enter an execution key in an input
• toggle each modifier on/off
• save macro
• show message/alert when macro is triggered

[patrickberkeley]

Possibly use https://github.com/healthsparq/ember-fountainhead. Their guides feature would allow us to expose the two features listed on this issue.

[jordpo]

I started to add some basic testing functionality that should improve local development under the dummy app -> #42.

Goal would be to create a Github Page with documentation and this ability to test out different behavior with the add-on and macro settings.