[12421] Add negative exception for spells 57508 - 57512

Close #106 because it's invalid
[12422] Fix possible crash due to [12409]

Thanks Schmoozerd for pointing
[12423] Implement spell 56072

Also add caster exception for spell 56505
[12424] Add support for XP-Gain disabling

Add CONDITION_XP_USER to be able to check if a player has XP-Gain enabled or disabled
Add SCRIPT_COMMAND_XP_USER to enable/disable XP-Gain for a player

Signed-off-by: Schmoozerd <schmoozerd@scriptdev2.com>
[12425] Implement CONDITION_GENDER Thanks to crackm for testing