Rudimentary BT device detection

As we want to switch form iBeacon to Core Bluetooth, this commit introduces a (very rough) device detection via Core Bluetooth. It’s still kind of hackish and lots of old beacon code is still in there, working on it :-)
Removed iBeacon Classes

This commit goes further in switching from iBeacon to Core Bluetooth. We removed all iBeacon classes and added the correct delegates to the Core Bluetooth classes.
- “ID”s are now called identifiers
- CWBluetoothAdvertiser creates an identifier UUID - since we can send arbitrary data as an identifier, why not use UUIDs?
- all delegate methods have been renamed properly to incorporate the notion of “devices” instead of “beacons” and “identifiers” instead of “IDs”
- CWDeviceID is not needed anymore and was removed
- when detecting a new device, no proximity is sent anymore. A proximity update will be sent shortly after the discovery anyway
- device detection notification of CWWebapplication is now done after we received a unique ID from the connected peripheral, not immediatly when we discover the peripheral. This is necessary because without an ID, we cannot identify the peripheral later on if we don’t have an ID.