* Handle graceful shutdown with unwinding
* Fix a race condition
* Avoid double exit deadlock
* typo: fix docs
* Fix ethkey cli compilation
* Fix all other cases panic_hook::set -> panic_hook::set_abort
* struct fields do not need to be public
* Add comments on why exiting AtomicBool is needed
Docopt handles `--help` automatically for us, however we've handled those
Errors the same as all others: by exiting with Return Code `1`, which is wrong
for a totally appropriate a quit on `--help`. Fortunately `docopt:Error`
provides an `exit` helper function that discriminates properly between fatal
and non-fatal errors and exist appropriately.
This patch makes sure we use that handy function in case we encounter such an
error in the CLI of ethkey, ethstore and whisper. Thus those are now giving
the appropriate Return code on `--help`.
fixes#8851
* Update `add_license` script
* run script
* add `remove duplicate lines script` and run it
* Revert changes `English spaces`
* strip whitespaces
* Revert `GPL` in files with `apache/mit license`
* don't append `gpl license` in files with other lic
* Don't append `gpl header` in files with other lic.
* re-ran script
* include c and cpp files too
* remove duplicate header
* rebase nit
