Add code examples to the spec

[jyasskin]

@slightlyoff requested either code examples in the spec or a prominent link to the explainer. Code examples are probably better for the spec itself to avoid versioning issues.

[jyasskin]

I'm going to remove the explainer for being out of date, so here's a list of things it intended to document that we don't have code examples for yet:

• [ ] Add a device using a non-standard UUID to show off the non-string interface.
• [ ] Show how to get all instances of a given service UUID, for example to support multiple battery services in a device.
• [ ] Show an example of querying a service's UUID to motivate the bluetoothUUID.get*() functions.
• [ ] [Not spec'ed yet] Register to get notified when a particular device comes in range. UA would present user with a dialog asking "which app do you want to handle this device?"
• [ ] Write a characteristic
• [ ] Read/write a descriptor

The existing examples could use more exposition, too.

[beaufortfrancois]

I believe we can close this one. @jyasskin WDYT?

[jyasskin]

I still don't have all the examples from my old comment. :-/