Finish the implementation of the new function getAddressesFromBondTable() in
SecurityManager that returns a table with a list of addresses from the peers
in the bond table.
The module is updated to comply with the changes to BLE API regarding correct
shutdown functionality. The following changes are introduced to ble-nrf51822:
* Calls to the old static function shutdown in Gap, GattClient, GattServer and
SecurityManager are removed.
* The cleanup function in Gap, GattClient, GattServer and SecurityManager is
renamed to `reset()` and made public.
* The static references inside nRF5xGap, nRF5xGattClient, nRF5xGattServer and
nRF5xSecurityManager to objects of their own class are moved to nRF5xn.
* The static getInstance accessors in nRF5xGap, nRF5xGattClient,
nRF5xGattServer and nRF5xSecurityManager are removed and their functionality is
moved to the implemented virtual accessors in nRF5xn i.e. getGap(),
getGattClient, etc.
* A static function Instance is added to nRF5xn class to make the transport
object accessible across the module.