WIP:Correct deprecations warnings raised into Nodejs v10

https://stackoverflow.com/questions/52165333/deprecationwarning-buffer-is-deprecated-due-to-security-and-usability-issues

• Consider Uint8Array as a string type

Unfortunately, this change introduces a bug: the PoW does no longer work.

changed milestone to %1.9

added M-prover label

changed the description

Fixed by !1292 (merged)

closed