fix handling of IO Capability Request if non-bondable

implemented gap_security_level getter

use link_key_type_t as defined in Link Notification Event

track link keys from PIN request as authenticated

add link_key_type to remote device db using LINK_KEY_TYPE_UNAUTHENTICATED as default

track encryption status

prototype gap security level API

read remote supported features and check for SSP on new connections

respond with hci_io_capability_request_negative_reply in non-bondable mode to io cap request

respond with pin code negative reply if in non-bondable mode

answer link key request in non-bonadable mode

add bondable flag to hci and provide gap_set_bondable_mode

use uint8_t for address type

track use of random addresses in hci

correct check for ACL packet length

check if hci_stack.control is set before accessing it in case of hardware error event

assert correct packet size for received ACL and event packets

wait for COMMAND COMPLETE(HCI_RESET) after initial HCI RESET command

added hci_local_bd_addr()

remove sketched code

Enable SSP by default: no I/o, auto accept

don't enable LE Meta Event for non-LE chipsets - fixes problem with Kensington/CSR 2.1 Dongle

store LE Buffer size

fix compile without HAVE_BLE

move common LE init code into hci.c