- defines RCconfig data structures
- adds method to read data
- use it in source files

- lock with mutexes
- don't start ENB_APP task, but Agent directly and wait in case of
  reconfiguration

- {restart,stop}_L1L2() in lte-softmodem.c
- add function start_phy_rrc() in enb_app.{c,h}, accessible from outside
- will be used to restart PHY and RRC when lte-softmodem is restarted

use only one FlexRAN wait function

*Fix the issue with the PDCP UE ID/RNTI management

physicalConfigDedicated may be legitimately NULL at some places
with the current code.

A cleaner solution is needed (we should always have a dedicated
config, initialized with values from the 3GPP specs, not have
a NULL as we do now).

Even if the old UE is not found, we have to cancel the random access.

changing of notation for Random-Access procedure to match documentation. Function remains the same. Indentation (-kr) run on all files in LAYER2/MAC

- remove global variables in the function lte_est_timing_advance_pusch
- do the smoothing logic that was in lte_est_timing_advance_pusch
  in rx_sdu (is it necessary? is it correct?)
- put back the value 100 in prach_procedures for the test on prach energy
- change the value of timing_advance_update

  it was:

     timing_advance_update                  = sync_pos - eNB->frame_parms.nb_prefix_samples/4; //to check

  it is now:

     timing_advance_update                  = sync_pos; // - eNB->frame_parms.nb_prefix_samples/4; //to check

  this should be checked somehow. The computation looked suspicious. Maybe
  the new one is wrong.