Typehinted up entity API

Did you guys think ALPHA7 changes were done?!
Sone stuff still needs some work, most notably data-properties can't be typed yet because they are just mushed into a couple of methods.

src/pocketmine/IPlayer.php

@@ -35,7 +35,7 @@ interface IPlayer extends ServerOperator{
 	/**
 	 * @return string
 	 */
-	public function getName();
+	public function getName() : string;
 
 	/**
 	 * @return bool