* stop the RU first, as it seems to prevent some deadlocks when soft-restarting
  the softmodem
* correct the formatting at the end of main

* join RU FH thread first as it depends on the others
* join RU FHTX only if it has been started (check as for pthread_create())
* join PRACH thread in the monolithic case

* init_td_thread()/init_te_thread() are only initialized depending on condition
  get_nprocs() > 2 && codingw
* apply the same the same for the functions kill_td_thread()/kill_te_thread()

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

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