unit/AVCTP: Add connection establishment dummy tests

Add some tests checking that L2CAP connection is established, so they
are basically dummy tests.
unit/AVCTP: Add test TP/NFR/BV-03-C

The test verifies that IUT (TG) correctly reports the parameters of the
incoming command in the handler callback.
android/unit: Fix checking for expected termination

This fix makes sure that when signalled termination is expected,
it actually happens. If IPC termination is expected no response will be
sent, so cmd_watch will never be executed. But if it is executed when
expecting termination, its a failure.
android/unit: Rename cmd handler

This handler responses for opcode == 1, thus should use proper naming to
avoid confision when more functions sending different responses will be
added.
android/unit: Add test cases for proper handler calls

This patch adds tests for calling proper opcode handler. Two handlers
are registered, but one always results in failure. No failure means that
proper opcode <-> handler maching is done by the ipc mechanism.
android/unit: Add case for opcode without handler

This test case checks if IPC shuts down on unhandled opcode.
android/unit: Add support for variable length data

This patch adds sending messages larger than just hal_hdr, and fixes
response verification which worked only for empty messages but was
failing when sending something more than just header.
android/unit: Add test case for variable sized data

Check if sending variable length data with proper msg size declared inside the
header succeeds.
android/unit: Add another case for variable sized data

This patch adds test for variable length data handling. Handlers struct
have static values representing minimum payload. It cannot be predicted
how large data will be sent so they should accept data larger than
declared inside ipc_handler array, which holds the minimum size of such
message.
android/unit: Add case for out of range service

Check reaction for sending message to services not listed inside
hal-msg.h
android/unit: Add negative case for msg size verification

Case for checking message size declared inside the header against the
amount of data sent for variable sized message.
android/unit: Add case for sending incomplete header

Header size is the bare minimum that should always be sent.
android/unit: Add cases for msg size verification

This patch adds checking for proper msg size verification in case it is
not declared in handlers that this is variable sized message. In
such case malformed data should not be accepted.
android/unit: Make tests names shorter
android/unit: Some codestyle cleanups
doc: Update test case numbers for Android IPC
android/bluetooth: Add threshold to RSSI change

There is no need to report very small RSSI changes.
android/bluetooth: Refactor update_found_device function

This function grown too big and was hard to follow. Split it to helpers
for clarity.
android/bluetooth: Send prop change event only if prop was changed
android/handsfree: Add initial files

This adds initial HAL and daemon code for Handsfree profile.