* 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

* 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

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

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.

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

UE directory splits, creation of UE-specific files, common UE/eNB files and extraction of UE/common components from eNodeB files. renaming of files to minimize common names across directories (i.e. defs.h, vars.h, extern.h)

has been introduced in commit 365ca71a

- remove spaces at the end of lines
- remove useless dead code
  use: git show -p <this commit> -w
  to see it clearly

all the FlexRAN scheduling code is now also handled by the general OAI
scheduling code