Introduce first version of TCP code.

Introduce first version of TCP code.

    Supported functionality:
    - open/close
    - listen/accept/connect
    - send/recv
    In order to achieve that libtle_udp library was
    reworked into libtle_l4p library that supports
    both TCP and UDP protocols.
    New libtle_timer library was introduced
    (thanks to Cisco guys and Dave Barach <[email protected]>
    for sharing their timer code with us).
    Sample application was also reworked significantly
    to support both TCP and UDP traffic handling.
    New UT were introduced.

Change-Id: I806b05011f521e89b58db403cfdd484a37beb775
Signed-off-by: Mohammad Abdul Awal <[email protected]>
Signed-off-by: Karol Latecki <[email protected]>
Signed-off-by: Daniel Mrzyglod <[email protected]>
Signed-off-by: Konstantin Ananyev <[email protected]>