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

slice_counter had a wrong condition, not scheduling in DLSCH if the number of
slices is greater than one

- introduce structure in RC for slicing conf (UL/DL)
- move global variables regarding slice configuration into RC
- change ue_slice_membership(): consider UL/DL
- remove the unnecessary header files
- set default parameters: one slice

Summary of changes:
- some work on better parallel processing of eNB
  try the eNB with options: --fepw --codingw
- small changes for multi-UE simulation and simulation accuracy
  (UE power levels)
- initial work for the UE to use TUN device instead of ue_ip.ko
  only done for oaisim, default bearer, compile with:
    ./build_oai --ue-nas-use-tun <rest of options>

158 does not work well with the eNB softmodem.

- fix compilation of dlsim/ulsim/oaisim by defining some needed
  global variables
- fix compilation of oaisim: compile coding and params_libconfig
- fix running of if4p5 with low CPU count (oaisim was not working
  on the machine 'haswell' because of this)

Merge remote-tracking branch 'origin/RU-RAU-split-parallel-EMUFH-phy-test-merge' into develop_integration_2018_w15

modifications for simulator : power normalizations for UE TX, small changes to SNR targets for power control, default UE power (23 dBm now)

This work is based on work by NTT.

To use the code, do:
./build_oai --oaisim --ue-nas-use-tun -t ETHERNET -c

This commit only handles oaisim in S1 mode.

We won't handle noS1 mode.