Try to merge feature-68-enb-agent into develop
develop should be fast-forwarded later to this branch to complete the merge
This code does not compile yet. Among other things:
- the scheduler structure needs to be reworked for FlexRAN
- the config is structured differently. The files enb_config.{c,h} from develop
  have been copied in here, the files with merge annotations are in
  enb_config.{c,h}.before_merge
- the restart needs to be restructured, since the PHY vars data structure lives
  in RC now