Edit the findScreenCenter method in camera

[cehrensperger]

-The method needs to check if the player is at the world border or not
--If the player is not the screen center should be the player position (Main.getPlayer.getPosX/Y();)
--if the player is at any of the world borders set the center to half the screen width (getWidth/Height() / 2;) away from that border.
---World border can be found from Tile.getAllTiles 2d array, get both lengths from that array and multiply them by
tile width (Tile.width)