Refactor the code so that fzf can be used as a library (#3769)

src/ansi.go

@@ -292,7 +292,7 @@ func extractColor(str string, state *ansiState, proc func(string, *ansiState) bo
 
 func parseAnsiCode(s string, delimiter byte) (int, byte, string) {
 	var remaining string
-	i := -1
+	var i int
 	if delimiter == 0 {
 		// Faster than strings.IndexAny(";:")
 		i = strings.IndexByte(s, ';')
@@ -350,7 +350,7 @@ func interpretCode(ansiCode string, prevState *ansiState) ansiState {
 	state256 := 0
 	ptr := &state.fg
 
-	var delimiter byte = 0
+	var delimiter byte
 	count := 0
 	for len(ansiCode) != 0 {
 		var num int