Remove compilation warnings, also fix telnet server compilation failure and NB-IoT shared lib compilation failure introduced when reviewing L1 sources  organization

Whenever the value T_BUFFER_MAX changes, the tracers had to
be recompiled. The only reason why it was needed is because we
used some fixed size buffers to read events. This commit removes
this restriction.

Also, with the basic simulator, this value T_BUFFER_MAX now comes
with an #ifdef which would have required some special hackish-level
tricks in the tracers, which is not good.

Let's just allocate memory when needed.

This commit introduces a 'basic simulator'.

This basic simulator is made of:
- the standard eNB code using a special driver that mimics the USRP driver
- the standard UE code using a special driver that mimics the USRP driver
- no channel simulation
- some special code to deal with faster-than-realtime behaviour of this
  basic simulator

It connects one UE to one eNB. It requires an EPC, populated with the
correct configuration for the UE.

This is the initial release and may contain bugs (most probably race
conditions due to the faster-than-realtime behaviour).

To use it, see the documentation at:
    targets/ARCH/tcp_bridge/README.tcp_bridge_oai.

It has been tested with 25, 50 and 100 RBs, FDD mode.
(No check at all has been done to know if it could work in TDD mode.)

That allows to run several programs using this mechanism on the
same computer (say both eNB and UE, to debug).

This commit fixes issues introduced by the previous commit.

Summary of work:
- cleanup:
  - fix LOG_XX to be less verbose
  - fix cmake_targets/CMakeLists.txt
  - fix oaienv
  - remove dead code
- bug fixes:
  - in openair1/SCHED/fapi_l1.c we had:
      eNB->pdcch_vars[subframe&1].num_dci           = number_dci;
    should be:
      eNB->pdcch_vars[subframe&1].num_dci           = 0;
    This bug let the PHY send more DCIs than what should have been
    sent because num_dci is incremented later on in the code.
    This fix may be a problem for fapi mode, to be checked.
  - add new T VCD traces
  - revert openair1/PHY/TOOLS/file_output.c to 'develop' version
  - remove thread_id in logRecord/logRecord_mt
  - revert (and adapt) configuration files
  - be careful when doing frame++, we need to % 1024
  - revert target_rx_power in openair2/LAYER2/MAC/eNB_scheduler_ulsch.c
- NFAPI:
  - the open-nFAPI code has been included in the repository. See nfapi/README.
    Maybe we should "git clone" the Cisco repository instead. We have to be
    careful of availability though.

What has been tested:
- monolithic eNB FDD 5/10MHz with one UE, iperf UDP/TCP uplink/downlink

Anything else may fail to work, especially the FAPI mode, which has not
been tested at all.

Sometimes when the user does ctrl+c to quit, it may not quit
if nothing comes on the socket. Closing the socket in the
signal handler fixes this.

Do not link the X stuff for tracers not needing it.

Later on, use this file with gtkwave.
To be used to check realtime behaviour of the system.

This tracer extracts output subframes generated by the eNodeB,
so they can be analyzed with some external tools.

This tracer extracts the content of a buffer field of an event
that was previously saved using the tracer 'record'.

For example, to extract the channel estimation done in
frame 924 and subframe 2 as saved in the file input_record.raw
and to store it in the file output.raw, do:

./extract -d ../T_messages.txt -o output.raw input_record.raw ENB_PHY_UL_CHANNEL_ESTIMATE chest_t -f frame 924 -f subframe 2

- UE_id 0 is for rnti 65535 (sib)
- UE_id 1 is for rnti 65534 (this is a hack)
- UE_id 2 is for rnti 2     (RA RNTI as of today's code/config)
- we start enb by displaying UE_id 3
- there was a bug: we need to lock when resetting UE ids (reset_ue_ids)

not finished, UE may not work, many things bad/to fix properly

- ENB_PHY_OUTPUT_SIGNAL to trace output signal
- ENB_MAC_SCHEDULING_REQUEST to trace scheduling requests

This program extracts a given subframe from a recorded trace.

We now have 4 versions of T_HEADER:
 - bad quality C++ version with time
 - good quality C version with time
 - bad quality C++ version without time
 - good quality C version without time

we want those traces in the logs people send to us and
the group HEAVY is disabled in the wiki instructions.

looks better