When history looks back at crypto years from now, the end of November 2018 will go down as a dark period. The drop in values over the past couple of weeks has been astounding, especially given what happened just before. Bitcoin started the month at $6,341, according to data from CoinDesk. The markets seemed content with prices remaining around that level. “Bitcoin volatility sinks to lowest in nearly two years,” proclaimed a Reuters headline on November 6. To be sure, weekly volatility—that is, standard deviation of prices—was at roughly 32 percent on an annualized basis, noted the piece. That was significantly lower than the 140 percent it experienced in February…