Update navbar.php

Temp test of Circulate Chrome Extension install via Bootstro.js popover.

Call via JS console with:

bootstro.start(".bootstro", {});
Update header.php

Added (for testing):
bootstro/bootstro.min.js
bootstro/bootstro.min.css
Create bootstro.min.css
Create bootstro.min.js
Merge remote-tracking branch 'remotes/github/startupTests'