obexd: Add obc_session_get_folder function

This patch extends client session by the tracking of the current folder.
The current folder can be accessed by obc_session_get_current_folder.

This allows drivers to add a folder property to browsed objects so that
the application doesn't have to keep track of the folder an object
belongs to.
obexd: Add property Folder to MAP message
obexd: Add property changed signals for 'org.bluez.obex.Message1'

This patch adds property changed signal emissions in case message properties
change on the server.
obexd: Fix disconnecting underline transport before processing operations

The transport connection should only be dropped once all references to
the session are released otherwise some pending operations may not be
processed and the session will not be freed.
emulator: Filter for valid packet types from /dev/vhci
lib: Add definition for HCI_CHANNEL_USER
build: Check for clock_gettime and pthread_create
monitor: Fix format string for UUID-128 print out
monitor: Add support for printing UUID-128 in ATT
build: Add test-driver to maintainer clean process
tools: Add command line options for btattach utility
core: Fix emitting empty Device1.UUIDs property

In case there is a incoming connection but services has not been
resolved the UUID of the profile being connected is automatically added
using btd_device_add_uuid which does update uuids not eir_uuids which is
used if svc_resolved is false.

To fix this the code will now fallback to uuids field whenever eir_uuids is
empty so uuids added with btd_device_add_uuid previous to services being
resolved should appear in UUIDs property.
tools: Make parameter argument variables const
tools: Add example utility to demonstrate user channel usage
lib: Add support for new Mgmt command

This patch added support for the new Mgmt command Load Auto
Connection Addresses.
DEBUG: btmgmt: Add dummy auto-conn command