Fixed bug with preventing Melira from putting +1/+1 counters on creatures you control
Reworked AVanishing (fixed bugs + more fair implementation)
Fizzle unless pay x (thanks to excessum)

- saves source card in storedSourceCard for ATransform
- adds support for WParsedInt in pay as "pay[[{value:WParsedInt}]]":

name=Spell Rupture
target=*|stack
auto=if cantargetcard(*|opponentstack) then transforms((,newability[pay[[{value:power:highest:creature:opponentbattlefield}]] name(pay {value} mana) donothing?fizzle])) forever
text=Counter target spell unless its controller pays {X}, where X is the greatest power among creatures you control.
mana={1}{U}
type=Instant

- adds support for {x} in *some* “pay” abilities (Syncopate):

name=Syncopate
target=*|stack
auto=transforms((,newability[pay[[{x}]] name(pay {value} mana) donothing?fizzleto(exile)])) forever
text=Counter target spell unless its controller pays {X}. If that spell is countered this way, exile it instead of putting it into  its owner's graveyard.
mana={X}{U}
type=Instant

- support of "name(pay {value} mana)" in pay abilities to show actual number to pay (see example above)