Draft: Shield Refactor

Todo:

• Fix fireflower not going away after being damaged. (FIXED)
• lib_pRemoveShield needs to be deprecated.
• Create an automatic compatibility layer for player.powers[pw_shield] in lua.
• Make player->shield accessible
• Remake fireflower detection, I realized that the fireflower cant be the only one accessible through SH_STACK
• ShieldThink Hook.
• expose more shield constants to lua.
• Shield freeslots! SHIELD_...

Additions

• Old shieldtype_t has renamed to legacyshieldtype_t and has been replaced with a brand new enum.
• New Lua function P_KillShield.
• player->shield [shieldtype_t] (C side only at the moment)
• player->shieldorb [mobj_t] (Both C and Lua)
• SHIELD_NONE exposed to lua

typedef enum 
{
	// Vanilla Shields
	SHIELD_NONE = 0,
	SHIELD_PITY,
	SHIELD_WHIRLWIND,
	SHIELD_ARMAGEDDON,
	SHIELD_PINK,
	SHIELD_ATTRACT,
	SHIELD_ELEMENTAL,
	SHIELD_FORCE,
    
	// Sonic 3 Shields
	SHIELD_FLAME, // SH_FLAMEAURA equivalent
	SHIELD_BUBBLE, // SH_BUBBLEWRAP equivalent
	SHIELD_LIGHTNING // SH_THUNDERCOIN equivalent
} shieldtype_t;

typedef enum
{
	SP_FIRE = 1<<0,
	SP_WATER = 1<<1,
	SP_ELECTRIC = 1<<2,
	SP_SPIKE = 1<<3,
} shieldprotection_t;

typedef struct
{
	shieldtype_t type;       // what shield it is SHIELD_...   (512 max shields for compatibility, can increase in 2.3 if player.powers[pw_shield] gets removed
	UINT8        hp;         // how many hits a shield has (used by force shield)
	UINT16       protection; // flags, similar to SH_PROTECTFIRE SH_PROTECTWATER SH_PROTECTELECTRIC SH_PROTECTSPIKE
	boolean      fireflower; // hardcoded fireflower stuff idk suggest something better
} shield_t;

typedef struct player_s
{
    // … existing fields …
    shield_t    shield;        // replaces powers[pw_shield]
    mobj_t      *shieldorb; // pointer to the active shield mobj (NULL if none)
    // …
} player_t;