v0.03 - Yrsa is added, and trees props are implemented

This update (v0.03) covers the following: 

• Yrsa's basic spritesheet is added to the game.
• Some mood handling is done for the Dialogue Manager. It will add the possibility of adding "happy", "surprise", "angry" moods to the characters.
• I created two types of props concerning trees, and added a component to make the transparency effect comes up when we are passing through the upper part of any of them.