Added NPCs

Still some bugs fixed...
But now there is more : NPCs (for quests, story ....)

Features :

• Tiled .tmx files supported
• Player class with input (arrow keys / ZQSD)
• Basic enemy that chase the player
• New graphics in retro style
• Basic enemy that shoots at the player
• Player can now kill enemies
• Player can now "listen" to npcs

The feature in action :