Update readme to indicate that you should use the --harmony flag

Test Plan:
- None
Add telemetry experiment video

Test Plan:
- Init data and make sure it shows up
Update localization files

Test Plan:
- None
Update react

Test Plan:
- None
Merge branch 'master' of https://github.com/bbondy/codefirefox

Conflicts:
	README.md
	locales/en.js