the integration of the nfapi-L2-emulator-for-develop (f254107b) added more
types in the RCconfig_flexran(), but they were partially wrong. This commit
fixes those types after the rebase of this branch on top of 2018.w19

* give the correct UE_id instead an index of the protobuf message (they can
  diverge from each other)
* in the PDCP part of the RAN API, the RAN API has to make the conversion UE_id
  (MAC) to UID (PDCP)
* a follow up commit could clean up the interfaces:
  - the MAC functions take the UE_id
  - the RRC functions take the RNTI
  - the PDCP functions take the UID
  this would mean the caller has to find those ID but would decrease
  computations since the RAN API functions do not have to do that themselves

* 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
    };