Science/Culture Overflow Bug Fix

For the sake of simplicity I only describe Science here, the same is true for Culture. What is Overflow Science? Suppose that your science yield is 30 Science per turn, and you're now researching Pottery, which cost 25 Science. On the next turn, Pottery is completed, and you will get 5 Overflow Science. If now you chose to a research Writing, which cost 50 Science, then on the third turn your research progress will be 35/50. Now consider the case that you switch to Mining (which also cost 25 Science) rather than Writing. Then on the third turn you will have 10 Overflow Science, with 5 comes from the first turn and 5 comes from the second. Bug about Overflow Science There are some bugs (or, features) about Overflow Science: You may only research one technology in a single turn. Suppose that your Science yield exceeds the Science cost of technologies a lot. Though excess Science is kept as Overflow Science, you can only accumulate it each turn, but never make use of it, even if the overflow itself is enough to complete a single technology. This becomes a real problem on later period of game when trying to get a quick Science Victory. Though completing a new technology, using turn-based science yield, will accumulate Overflow Science, but using abilities that grant one-time science within a turn (for example, Great Scientist Margaret Mead, which gives 1,000 Science when activated) will not. Suppose that you now have 1,000,000 Overflow Science, and activate Margaret Mead on a 100-cost technology. Then the technology is completed, but your 1,000,000 Overflow Science will be lost and replaced by 900 Overflow Science from Margaret Mead. Also, using abilities that grant one-time science will not make use of Overflow Science. Suppose in the above case you active Margaret Mead on a 2,000-cost technology. Then you'll get research progress 1,000/2,000, and your 1,000,000 Overflow Science stays where it is. How did I fix it? I added a virtual technology called the Overflow Techn