neard: Fix checking for unknown carrier power state

Message might not contain State field and CPS needs to be set to
unknown before processing message from neard. This fix processing
RequestOOB called without parameters.
neard: Fix reading local OOB data when adapter is not powered

Read Local OOB data only if adapter is powered. This fix replying with
error instead of CPS set to inactive when adapter is not powered.
device: Add function to find a given service

Search within the list of services for a given remote UUID.
profile: Fix remotely initiated connections without service

Remotely initiated connections need to be associated to a service
instance to avoid the following crash as reported by Vinicius Costa:

bluetoothd[14366]: src/profile.c:ext_confirm() incoming connect from A0:4E:04:F6:F5:05
bluetoothd[14366]: src/profile.c:ext_confirm() hfp_hf authorizing connection from A0:4E:04:F6:F5:05
bluetoothd[14366]: src/agent.c:agent_ref() 0x6a85e0: ref=2
bluetoothd[14366]: src/agent.c:agent_authorize_service() authorize service request was sent for /org/bluez/hci0/dev_A0_4E_04_F6_F5_05
bluetoothd[14366]: src/profile.c:ext_svc_complete() Services resolved for A0:4E:04:F6:F5:05
bluetoothd[14366]: src/profile.c:ext_svc_complete() Services resolved but still waiting for authorization
bluetoothd[14366]: src/profile.c:ext_auth() A0:4E:04:F6:F5:05 authorized to connect to hfp_hf
bluetoothd[14366]: src/agent.c:agent_unref() 0x6a85e0: ref=1
bluetoothd[14366]: src/profile.c:ext_connect() hfp_hf connected to A0:4E:04:F6:F5:05

Program received signal SIGSEGV, Segmentation fault.
btd_service_connecting_complete (service=0x0, err=err@entry=0) at src/service.c:315
315		if (service->state != BTD_SERVICE_STATE_DISCONNECTED &&
profile: Error-cases for incoming connections

When an incoming connection attempt is received, if the corresponding
device or service is not found, handle the error-case.
core: Don't update a known long name with a short name.

update_found_devices() could attempt to update a device with new information
containing only a short verstion of the name. If the struct eir_data passed
has a short or NULL name, it will never update a previous name and will
also trigger a "HCI Command: Remote Name Request" if the previous name was
unknown.
gdbus: Fix segfault when D-Bus daemon exits

Fix this crash if D-Bus exits while the client is still connected to it:

==5570== Invalid read of size 1
==5570==    at 0x402D28E: strcmp (in
/usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
==5570==    by 0x4070E22: g_str_equal (ghash.c:1704)
==5570==    by 0x8055F61: message_filter (client.c:1123)
==5570==    by 0x4141500: dbus_connection_dispatch (in
/lib/i386-linux-gnu/libdbus-1.so.3.5.8)
==5570==    by 0x80506F7: message_dispatch (mainloop.c:76)
==5570==    by 0x4081A7E: g_timeout_dispatch (gmain.c:3882)
==5570==    by 0x4080D85: g_main_context_dispatch (gmain.c:2539)
==5570==    by 0x4081124: g_main_context_iterate.isra.21 (gmain.c:3146)
==5570==    by 0x408156A: g_main_loop_run (gmain.c:3340)
==5570==    by 0x41BF4D2: (below main) (libc-start.c:226)
==5570==  Address 0x0 is not stack'd, malloc'd or (recently) free'd
==5570==
==5570==
gdbus: Fix using NULL DBusPendingCall when disconnected from D-Bus

From D-Bus documentation for dbus_connection_send_with_reply():

"Warning: if the connection is disconnected or you try to send Unix file
descriptors on a connection that does not support them, the
DBusPendingCall will be set to NULL, so be careful with this."

Fix these errors when killing D-Bus daemon with the client still
running:

process 5712: arguments to dbus_pending_call_set_notify() were
incorrect, assertion "pending != NULL" failed in file
../../dbus/dbus-pending-call.c line 596.
This is normally a bug in some application using the D-Bus library.
process 5712: arguments to dbus_pending_call_unref() were incorrect,
assertion "pending != NULL" failed in file
../../dbus/dbus-pending-call.c line 572.
This is normally a bug in some application using the D-Bus library.
core: Convert the pincode callback to an interable list.

The current pincode callback list on the adapter keeps track of all the
pincode callbacks registered by a plugin for that adapter and calls each
one until one provides a pincode for the current bonding. This mechanism
forgets about what happened with previous bonding attempts and pushes
the status track to the plugin side.

This patch creates an iterator struct (struct pincb_iter) that keeps
track of the last function called and the number of times called. This
will allow to provide more information about the bonding status to the
pincode callback.
plugins: Extend the pin code callback with the call number

The plugin's pin code callback doesn't know about the pairing process.
It just provides a pin code based on the information provided to this
function. Although limited state could be added through other new
callbacks, this fix achieves this by providing more information to the
callback itself. The new argument "attempt" states the pin callback
attempt of the particular plugin for the current pairing of the device.
This allows a plugin to try different pincodes for the same device in
the same pairing process.

To signal that the plugin doesn't provide any pin code for the provided
device the current implementation returns 0 (an empty pin code).
Analogously, with this fix, a plugin should return 0 when it doesn't
have any other pin code to provide for the given device.
core: Add support for retrying a bonding

In order to retry a bonding we need a timer that will perform the retry,
we need to stash the status of the bonding request so we can use it
again. In the case of a retrying bonding attempt we need to not tear
down the temporary D-Bus device object on the adapter.
core: Retry bonding attempt until the iterator reaches the end

This patch splits the bonding process in an interative process
consisting of one or more "bonding attempts". The user/agent starts a
new "bonding" that may involve several rounds of "bonding attempts" with
the device before it gets back to the user/agent.

Some functions were split in two parts to reflect this change. When a
bonding attempt fails with an authentication error and a pin code was
provided, a new bonding attempt is initiated (after a short delay) to
retry with the next function (or next call to the same function) in the
pincode callback list. If no pin code was provided to the device, no
retry is attempted and the authentication error is returned to the
client. This effectively allows a plugin try different pincodes for the
same device during the same bonding.
core: Add device_get_class to the public interface

Exports the device class to plugins.
autopair: Add the autopair plugin

The autopair plugin tries standard pincodes for different devices with
dumb pincodes. It also generates a random 6 digit pincode for keyboards
that support any pincode but fallbacks to the agent call in case the
random generated pincode didn't work.
core: Expose the last bonding attempt timeout on retry

One of the interesting values for pincode plugins is the timeout of a
bonding attempt. For keyboards supporting any random pincode as long as
it is also typed in the keyboard, the timeout until it fails is in the
order of the seconds to allow the user type the pincode on the bluetooth
keyboard. In the case of a dumb keyboard accepting only a fixed pincode
the timeout before the keyboard fails is in the order of a fraction of a
second.

This patch computes the elapsed time between the pairing started or the
pin code was sent to the device and the device returns with an error.
This measured duration is exposed in milliseconds to the plugins when
retrying the bonding attempt.
autopair: Try a fixed pincode for keyboards rejecting random codes

This patch makes the autopair plugin try a fixed "0000" pincode for
keyboards that reject the pincode too fast (less than 500ms). This too
short delay rejecting the pincode means that the user didn't have time
to type the random pincode in the bluetooth keyboard and was the
keyboard who actually rejected it.
autopair: Clean up coding style
doc: Document missing errors returned by the Device1 API.

There were two groups of missing error messages in the documentation:
* For org.bluez.Device1.DisconnectProfile:
  This method could certainly call btd_error_not_supported or
  btd_error_failed returning those errors.
* For org.bluez.Device1.Pair:
  The pairing process could certainly call new_authentication_return
  which can return (and actualy does) five other different errors.
AVCTP: Add support to register pass-through handler

Pass-through handler can be used to capture AV/C Panel commands before
they are sent to uinput.
AVCTP: Don't allocate memory for every key pressed

The timer field can be used to detect if the key is currectly active
instead of relying on a pointer that needs to be allocated for every
single key press.