Patch 2.5.0: Tier 4+5 unit buffs, Necro nerf, and 2 new 800 Blood Shards achievs

[b] Buffs:[/b] Griffins from +4 to +5 damage each attack. Arch Angels passive heal from 40 to 50 every 2nd second. Frost Giant passive freeze chance from 30% to 37%. [b]Nerfs:[/b] Necromancer attacks to summon Undead Dwarf from 6 to 7 (Still summons after the first attack in start of the round). [b]Two new achievements: [/b] Defeat Arena on brutal or harder with [b]max 800[/b] Blood Shards spent on upgrades. Defeat Forest on brutal or harder with [b]max 800[/b] Blood Shards spent on upgrades. I have also updated the Behold Battle demo, adding a gold betting mode, and improved both the normal game mode and the sandbox/simulator game mode. Check it out at: https://store.steampowered.com/app/2338910/Behold_Battle/