Added formatParse to FlxText: t.text="show $green text$ between dollar s...

...igns"; t.formatParse([greenFormat],["$"]);

(Trying this again)
The former issue could be avoided by abstracting the format and its marker into an object:

```haxe
typedef FormatMarkerPair = 
{
   format:FlxTextFormat,
   marker:String
}
```

That would mean an `Array<FormatMarkerPair>` is used.