Start drafting iOS 7 web app post

I already did the legwork, just need to write the post.
Add new iOS 7 icons

Also reorder them based on my own advice (largest to smallest).
Draft iOS 7 web app post
Split <head> stuff into includes

Much easier to reason about this way.
Clean up includes
Re #16; improve Windows tiles
Fix #16; add note about My Pinned Site
Fix #15; update Google+ URL
Cross-link posts
Paramaterize author
Finalize post
Merge pull request #14 from tfausak/ios-7-web-app

iOS 7 web app