The shell expansion syntax used in the run_node script was not handled properly
by the bash shell shipped with macOS. In particular, it was not able to handle
range expressions involving interpolated vars:
cp foo/{$FIRST_INDEX..$LAST_INDEX} ...
To enable it, comment out the 'withLibp2p' line in nim.cfg
The history was squashed in order to remove an accidentally
commited binary file.
Other changes:
* SSZ was adapted to use the common serialization framework
* gossibsup.subscribe is not using async handlers at the moment
and this allowed me to simplify it
Zahary Karadjov