Create sim primer

[arouinfar]

Tracking sim primer creation in this issue so that #1 can be closed.

Target Deadlines

• [ ] Script drafted by 4/14/17
• [ ] Script reviewed by 4/28/17
• [ ] First recording by 5/12/17
• [ ] Primer live by 6/1/17

[pixelzoom]

@arouinfar status of this? Should it be labeled "priority:2-high"?

[ariel-phet]

Should not be labelled high priority, changing to medium

[arouinfar]

The Unit Rates primer has been published to the website. Progress was discussed in the #primers channel on Slack, but here are the milestones:

• 10/10/2017: AR and CW collaboratively scripted the Shopping and Shopping Lab screens
• 10/16/2017: AR and CW collaboratively scripted the Racing Lab screen
• 10/20/2017: CW uploaded draft recording for script verification
• 10/24/2017: AR reviewed draft, and suggested script tweaks
• 11/1/2017: CW uploaded an updated recording
• 11/8/2017: AR reviewed the recording, and approved it for production
• 11/13/2017: CW uploaded the primer to Vimeo and captioned it
• 11/13/2017: AR reviewed the captions, and suggested a few edits
• 11/28/2017: CW made the requested edits, and published the primer to the PhET site