Add explicit README

[MondayHopscotch]

Just so we don't forget any steps that are needed, add an explicit readme that tells us how to get things setup.

• Metrics setup
• FMOD (are there any steps here?)

[Kenoshen]

We should also add a note about how to get started:

Getting Started

• run the init.sh script
• test it out with lime test html5 -D <yourname>