add: copeland vote procedure (untested)

comsoc/Copeland.go

-package comsoc
\ No newline at end of file
+package comsoc
+
+func CopelandSWF(p Profile) (count Count, err error) {
+	count = make(Count)
+	alts := make([]Alternative, 0)
+	for i := 1; i <= len(p[0]); i++ {
+		alts = append(alts, Alternative(i))
+	}
+	err = checkProfileAlternative(p, alts)
+	if err != nil {
+		return nil, err
+	}
+	for alt1 := 0; alt1 < len(p); alt1++ {
+		for alt2 := alt1 + 1; alt2 < len(p); alt2++ {
+			score1, score2 := 0, 0
+			for _, pref := range p {
+				if isPref(Alternative(alt1), Alternative(alt2), pref) {
+					score1++
+				} else {
+					score2++
+				}
+			}
+			if score1 > score2 {
+				count[Alternative(alt1)]++
+			} else if score2 > score1 {
+				count[Alternative(alt2)]++
+			}
+		}
+	}
+	return
+}
+
+func CopelandSCF(p Profile) (bestAlts []Alternative, err error) {
+	count, err := MajoritySWF(p)
+	if err != nil {
+		return nil, err
+	}
+	return maxCount(count), err
+}