Keyword order

Continuing from the discussion here https://github.com/HaxeFlixel/flixel/pull/829

The general consensus on the order seems to be:


1. public / private
2. static
3. inline

Undecided:
- Whether `override` should follow the most popular convention of being first or if as @crazysam suggested it might go before `private` `public` ? I am not too fussed if everyone agrees, but I wouldn't go against the trend of override first my own code. Is it C# libraries do this more?

So this is the keyword order change starting with functions (variables should follow), 
So far these commits change:

```
inline static public function
->public static inline function


static private function
->private static function


static public function
->public static function


inline private function
->private inline function


inline public function
->public inline function
```

Intellij's ui is letting me commit to `flixel-addons` and `flixel-demos` simultaneously so I'll push those as well once we have come to consensus.