Rare spell tome

Makes spell books rare. Most significant impact on store inventory, but also affects loot. Compatible with the Apocalypse Spell Pack. Designed for but not required spelling study.

Each teir's spells now have a certain chance of appearing (per tome), which can be edited using globals - as of V3.0, these globals are divided into "loot" and "shop" versions of each, allowing for configuration of loot and merchant rarities.

Novice: 70% - The store global is 0SpellTomeNoneShop, the loot global is 0SpellTomeNoneLoot, both default to 30

Apprentice: 50% - The shop global is 25SpellTomeNoneShop, the loot global is 25SpellTomeNoneLoot, both default to 50

Adept: 30% - The store global value is 50SpellTomeNoneLoot, the loot global value is 50SpellTomeNoneLoot, both are set to 70 by default

Expert: 10% - Shop global is 75SpellTomeNoneShop, loot global is 75SpellTomeNoneLoot, both default to 90

Changing these global variables to different amounts increases or decreases rarity, but does not affect merchants until they replenish their inventory.

This doesn't touch the master level spells for two reasons: 1) fiddling with variables and task content would be troublesome, 2) they only appear in a single instance anyway - seems rare to me.

This only works with Apocalypse, with a minor patch (actually USLEEP's patch, not this mod), and should work with any other spell mod that adds its spells to the tier list via script (tested to work with Mysticism-The Lost Art and Frostfall).

Additionally, the mod edits the Court Wizard merchants' chests to prevent them from selling only one large tome, and the Riverwood Traders' inventory chests to remove the starting spell from them.