In my journey to learn about mediation, I thought Roger Fisher and William Ury’s “Getting to Yes” was gospel — until I happened to read Chris Voss’ “Never Split the Difference: Negotiating as if Your Life Depended on It.”Voss was a top-level hostage negotiator who dealt with every manner of bad guy. In his cases, there were no win-win situations, and he couldn’t exactly agree to split the difference and let the terrorist kill two of four hostages.He boasts of humiliating the …