Struct implementation of an item's odds and relevant functions:
* Stored in an unordered map for non-static item allocation; you can theoretically have millions of items in the game now
* All item odds are dynamic C++ vectors that are loaded in a per-gametype basis.
* Extremely boilerplate; any and every system in place can be used by any and every item
* Changed every instance of K_AltShrinkActive to its K_IsKartItemAlternate equivalent
* Same as above for Invincibility; some functions might still rely on K_GetKartInvinType though
* (Balance change) Alt. Invin. needs a slightly farther distance to start appearing, hopefully means less 5sec dud invinces
* Brought back cv_landmine to prevent SIGSEGVs in the item toggles menu
* Introduce NUMBASEKARTRESULTS since all KAITEM_X items are overrides assigned via K_GetAlternateVersion
* Player gains a big speed boost
* Anything that would squish a shrunken player in Legacy (save for Grow players) flips them over here
* Most items rolled are doubled: singles become doubles, doubles become quadruples, and you can roll 6 bananas
* Certain multi items (3sneaker, 3orbi and 4orbi, 2jawz, decanana, ballhog) do NOT get doubled for balance reasons
* Shrunken players get rival bot odds, making their rolls more aggressive and frantic
* Guest star: fixed-point item bar
* Bubble scaling and shards have been refined
* No more passive protection against explosives and thunder
* The bubble boost timer now protects you from mine explosion particles, not
just flashtics, making it easier to pass through proxmines
* The bubble remains inflated after holding the button, and slowly deflates
* Popping the shield now gives you flashtics, in addition to the speedboost
* Popping it also makes you invulnerable to proxmines!?
* Getting hit by an item while the shield is deflated protects you from
JUST the spinout exactly ONCE, geez, think of the poor D5 players
* Players can be bumped by the inflated shield again, but it's very weak
* Bumping players with a deflated shield depletes half its HP, inflated
bumps cost the same as other bumps
