Remove limit on science cost multiplier

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A limit to 1000 on the science multiplier was introduced about 9 years ago, but surely a better solution to this can be had, where the calculated cost of technologies are capped to avoid overflow; thus removing the artificial cap on the science multiplier. I'd be surprised if the code doesn't already support that, considering that there are infinity techs, that even with a multiplier of 1 would eventually hit the limits of 64-bit integers.