Includes:
- print error message instead of forwarding posix signals in ns3
- supress printing of "Finished executing commands..." for ./ns3 run
- fix ns3 typos and formatting issues
- add verbose options and make doxygen/doxygen-no-build verbose
- re-enable printing of build messages in ./ns3 run
- refactor ns3 dry_run, quiet, jobs and verbose arguments
- check if examples subdirectories have a CMakeLists.txt
72e6105195