Working with Indexed DB

[addyosmani]

ILT content: https://docs.google.com/document/d/1JzsKnn8jP7B9CND_A_gnXt9-hkY5qLwZ1L92amsefhY/edit#heading=h.vngk1eevgbe2 (note this has already been reviewed)

Would make for a good primer on modern web storage.

Feel free to also crib/ref anything useful from https://medium.com/dev-channel/offline-storage-for-progressive-web-apps-70d52695513c#.p04f2r2je

[addyosmani]

cc @drufball as an FYI

[mco-gh]

Cross linking with related issue to add a storage overview page.

[mco-gh]

@addyosmani @drufball
I'm starting this now and, given it's supposed to be a tutorial kind of flow, I'm thinking I'll go straight to a codelab format and then we can use it both here in WF and for the Chrome Dev Summit as well. Any objections/concerns?