Added Tutorial and Various Menu Tweaks

Added a tutorial. The gameplay is straightforward for some, but it is difficult for most (especially for those that don't know how to hit ESC to look for controls like any other game).

Also updated the Level Up screen to be much more clear. All menus are still bare-bones and lack animations, I don't know if I'll be motivated enough to make them fancier cause, who am I kidding, no one is actually playing this game.

Note: if the "Gain Strength" button is disabled for you during level-up, please update to Spellcraft_0.5.5fix