Add a readme for iBeacon program
Add a serial_debug project

- shows how to use UART to write debug output
  to your computer
Minor README layout improvements

- moved toggle_led README into its own project
Add an ANCS demo

- Shows how to have an embedded device
  interface with Apple's Notification Center Service
- Able to subscribe to notices, as well
  as use the attribute metadata functionality
Merge branch 'ancs_rebase'