Add support for specifying both foreground and background colors.

.gitignore

@@ -1 +1,2 @@
 *.swp
+*~

escape.go

@@ -191,39 +191,59 @@ func (ei *escapeInterpreter) output256() error {
 		return ei.outputNormal()
 	}
 
-	fgbg, err := strconv.Atoi(ei.csiParam[0])
-	if err != nil {
-		return errCSIParseError
-	}
-	color, err := strconv.Atoi(ei.csiParam[2])
-	if err != nil {
-		return errCSIParseError
-	}
-
-	switch fgbg {
-	case 38:
-		ei.curFgColor = Attribute(color + 1)
+	for _, param := range ei.splitFgBg() {
+		fgbg, err := strconv.Atoi(param[0])
+		if err != nil {
+			return errCSIParseError
+		}
+		color, err := strconv.Atoi(param[2])
+		if err != nil {
+			return errCSIParseError
+		}
 
-		for _, param := range ei.csiParam[3:] {
-			p, err := strconv.Atoi(param)
-			if err != nil {
-				return errCSIParseError
+		switch fgbg {
+		case 38:
+			ei.curFgColor = Attribute(color + 1)
+
+			for _, s := range param[3:] {
+				p, err := strconv.Atoi(s)
+				if err != nil {
+					return errCSIParseError
+				}
+
+				switch {
+				case p == 1:
+					ei.curFgColor |= AttrBold
+				case p == 4:
+					ei.curFgColor |= AttrUnderline
+				case p == 7:
+					ei.curFgColor |= AttrReverse
+
+				}
 			}
+		case 48:
+			ei.curBgColor = Attribute(color + 1)
+		default:
+			return errCSIParseError
+		}
+	}
+	return nil
+}
 
-			switch {
-			case p == 1:
-				ei.curFgColor |= AttrBold
-			case p == 4:
-				ei.curFgColor |= AttrUnderline
-			case p == 7:
-				ei.curFgColor |= AttrReverse
-			}
+func (ei *escapeInterpreter) splitFgBg() [][]string {
+	var out [][]string
+	var current []string
+	for _, p := range ei.csiParam {
+		if len(current) > 0 && (p == "48" || p == "38") {
+			out = append(out, current)
+			current = []string{}
 		}
-	case 48:
-		ei.curBgColor = Attribute(color + 1)
-	default:
-		return errCSIParseError
+		current = append(current, p)
 	}
 
-	return nil
+	if len(current) > 0 {
+		out = append(out, current)
+	}
+
+	return out
 }