Added difficulty levels

Difficulty Levels Explanation

• Easy: Player starts with more health and mana. Health, mana, and damage grow faster as the player levels up. Reduced friendly fire.
• Medium: The default as currently found in the game
• Hard: Enemies grow in power by days passed, instead of progression through the campaign. Dying has a small chance to lose equipment. You don't recover health at the end of missions. Fewer allies are willing to help you on optional solo missions. Slightly increased friendly fire.
• Impossible: All the challenges of hard difficulty, but with a greater magnitude. The player has less health and mana. Roaming enemies are more likely to attack villages and the player's castle as time goes on.

Updated Items

1. Avatar unit orders to select melee / ranged units by type now accounts for actually equipped weapon, not just the recruitment category
2. Scale tower spellbook research from 1 to 2 times from campaign start to campaign end
3. End of level screen expanded to show more items.
4. Goblin dodge back animation now takes full damage if the player hits during the dodge
5. Wandering Mania: Units that die from physics damage are now credited to the player, to account for push and fall kills
6. Wandering Mania: Setup preliminary difficulty levels.
7. Orgasinator: Increase black enemy castle pathfinding region and add missing enemies