Create Sim Primer

[arouinfar]

For #1

• [x] Draft script - 08/14/18
• [x] Record rough version for script verification - 08/20/18
• [x] Review script verification draft, and adjust script as necessary - 08/21/18
• [x] Record another draft - 08/31/18
• [x] Review 2nd draft - 09/4/18
• [x] Produce primer and upload - 09/11/18
• [x] Caption primer - 09/11/18

[arouinfar]

@CWilson4960 the script is ready for recording. For the first draft, rc.3 will be fine. https://bayes.colorado.edu/dev/html/masses-and-springs/1.0.0-rc.3/phet/masses-and-springs_en_phet.html

[arouinfar]

The primer is produced and ready for sim deploy.

[arouinfar]

Since the primer appears in the master checklist, I'll go ahead and close this issue.