Mitopian Uprising - MI Alliance Addon

Huge technical change: Mitopian Uprising now has actual mod elements, meaning, most custom items are now actually new items and not just repurposed existing items! Because of this:
-Added a Creative tab for Mitopian Uprising so getting custom items is easy.
-NeMisis's crown is now placeable and looks unique!
-The Pride of NeMisis no longer breaks blocks in Creative mode!
-Fixed various bugs caused by repurposing vanilla items, like viewing incorrect recipes in JEI.
-Existing custom items from 1.1.0 will break. Sorry! Fortunately, it's easy to give yourself replacements now.

Added the Inactive Relicoid Core, rarely dropped from Relicoid or crafted with an expensive recipe for unlucky players. It can be crafted into some Runed Metal or given a Memory to activate it.
Added the Active Relicoid Core, used instead of a Memory to begin the Pristine Relicoid encounter.
Some tools now function in the offhand as well as the mainhand.
Mitopian Uprising item crafting recipes unlock in the recipe book at appropriate times.
Advancements for defeating bosses are now only granted if the player is nearby a boss when it's defeated, not just by holding their main loot items.
Boss advancements are broadcasted in chat. Log advancements still aren't for consistency with MI Alliance.

Fixed the Letter of Mocking not being cleared on use. This wasn't actually related to the custom item overhaul, so it gets mentioned here.
Fixed NeMisis visually not despawning right.