* instead of the lengthy YAML parsing, can now handle protobuf message
* after setting the parameters, send a message to ENB_APP to perform it
* old YAML way still works

* properly allocate memory for scheduler name/sorting
* free mem of sc_update, include todo for slice_config
* set has_x to one, add fct whether sorting update necessary
* set n_ul/n_dl to correct value after every loop iteration
* support for delete of multiple slices
* allocate memory for scheduler name in slice_config
* check that we really set the scheduler

- in order to facilitate the steps as verification and parameter setting,
  slices are "filled up" with default values:
  * if it is an update, with the values of the concerned slice
  * if it is a new one, with the parameters of slice 0
- because of this, it can be assumed that all slices have all parameters

- setter & getter have been renamed
- setter sets scheduler name and links to the corresponding function
- it also returns whether it succeeded (whether the scheduler callback is
  non-null)
- it performs a strdup on the scheduler name
- the remove function free the scheduler function name

- until now, on every iteration, the scheduler checked for changed parameter
  (and verified some)
- this functionality moves to the FlexRAN Agent, which verifies all parameters
  * individually, e.g. Max MCS <= 28 for DL
  * group-based, e.g. the sum of slice percentages is <= 100
- slice configuration changes are only applied if all verifications pass
- it is assumed in the scheduler, that configuration passed from outside is
  correct and can be used "as-is"

fix accounting setting

Prevent sc_update from being changed by an incoming slice reconfiguration
change while writing data to the scheduler

- flexran_agent_ue_config_reply() and flexran_agent_ue_state_change() send
  slice_id

Incoming slice configuration changes are buffered in an intermediate structure.
The MAC scheduler periodically polls the agent about changes. If there has been
a slice configuration change, apply it.

adds support for:
* create/remove slices
* change UE-slice association
* read/write slice parameters
* find slice index via ID

Use common log mechanism in layer 3, mapping specific macros to common ones and extending common log utilities to support specific layer3 requirements

LOG_F replaced by LOG_DUMPMSG. Add a generic function to dump a buffer or message. Go on with LOG_M implementation improvement. Remove redundant options to enable/disable logs.

The configuration file has now to contain ENB_IPV4_ADDRESS_FOR_X2C and
ENB_PORT_FOR_X2C in the NETWORK_INTERFACES section.

For example:

    NETWORK_INTERFACES :
    {
        ENB_INTERFACE_NAME_FOR_S1_MME            = "eth0";
        ENB_IPV4_ADDRESS_FOR_S1_MME              = "192.168.12.111/24";
        ENB_INTERFACE_NAME_FOR_S1U               = "eth0";
        ENB_IPV4_ADDRESS_FOR_S1U                 = "192.168.12.111/24";
        ENB_PORT_FOR_S1U                         = 2152; # Spec 2152

        ENB_IPV4_ADDRESS_FOR_X2C                 = "192.168.12.111/24";
        ENB_PORT_FOR_X2C                         = 36422; # Spec 36422
    };

As reported by Konstantinos Alexandris and Robert Schmidt.

USRP addressess and clock sources can be configured in the configuration file with the RU section with comma separated IP addresses in 'sdr_addrs' and with strings "internal"/"external"/"gpsdo" in 'clock_src'.

TODO: Currently the driver picks the two first RX and TX channels when nb_tx and nb_rx are both set to 2. If a developers wants to force usage of two devices, 'set_rx_subdev_spec' and 'set_tx_subdev_spec' can be used to indicate to the driver so that antennas from separate devices will be used. To rephrase: until 4 antennas are supported by OAI, testing with two devices, so that antennas from both devices are used, requires manual configuration of which subdevices' antennas are used.

Conflicts:
	targets/ARCH/USRP/USERSPACE/LIB/usrp_lib.cpp

remove compilation warnings, especially when disabling T_TRACER. enhance LOG_M macro implementation, introduce LOG_DEBUG_XXX macro to replace #ifdef DEBUG_XXX

log.c simplification, fix usefull functionality which never worked, move all log code from openair2 to common

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