Upcoming Major Riecoin 0.20 Upgrade

A new major Riecoin upgrade is planned, and includes a hard fork. I worked on it during the last few weeks.

The first step of this upgrade was to update the base code to Bitcoin's 0.20, which is done. You can find the experimental code at the Github repository. I also built experimental binaries. Despite their prerelease status, they should work fine and be fully compatible with current 0.16 nodes, though please backup your wallets if you plan to use 0.20, just in case. Feedback is welcome!