Support GATT services over BR/EDR.

Preview at https://rawgit.com/WebBluetoothCG/web-bluetooth/support-bredr/index.html

@armansito
As far as I know, the EIR doesn't distinguish between GATT and non-GATT services, so the UA wouldn't necessarily be able to filter out supporting the UUID the site requested over non-GATT. This would lead to the user selecting a device, and then the site not being able to retrieve any services from it. I think I want to call that a site bug instead of demanding that we connect to every BR/EDR device to figure out what kind of services it's offering.