* 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
Add --min-gas-price (does the same as legacy --gasprice) and tweak
gas_pricer_config() and test cases. Dev preset will still be
overridden by CLI arguments, including --gasprice.
