Automated hard fork signaling to the network

[kantp]

Node operators signal their readiness for the hard fork to the network, and the nodes automatically switch over to the hard fork version only when a sufficient amount of stake has signaled their readiness to switch over (as measured, for example, by some predetermined number of blocks in an epoch produced by node operators who have signaled their readiness to switch). This might be included in the original solution, or as a later upgrade.