Revert "Revert "add virtual dtor's for scheme's in new BLS impl""
Revert "Revert "add virtual dtor's for scheme's in new BLS impl""

This reverts commit 03e381dc7f3a91c1186cefa2b4b81d9434dd829f.

syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin